Investigation of Electrical Characteristics and Trapping Effects in p-GaN Gate HEMTs Under Electron Irradiation
在电子辐照下 p-GaN 门 HEMT 的电气特性和捕获效应的研究

Zixuan Feng $^{\oplus}$ , Shiwei Feng $^{(}$ , Shijie Pan $^{(}$ , Xuan Li $^{(}$ , Binyu You, Boyang Zhang, Yaning Wang,
冯子轩 $^{\oplus}$ , 冯世伟 $^{(}$ , 潘世杰 $^{(}$ , 李轩 $^{(}$ , 游彬宇, 张博阳, 王雅宁,Yamin Zhang $^{\oplus}$ , and Xiang Zheng $^{\oplus}$
张亚敏 $^{\oplus}$ ，和郑翔 $^{\oplus}$

Abstract 摘要

In this work, the variations of the electrical properties and trapping effects of p-GaN gate highelectron-mobility transistors (HEMTs) under 1-MeV electron irradiation were investigated systematically. When the irradiation fluence was increased, the drain-source current and the gate leakage current also uprose, but the threshold voltage shifted toward the negative direction. Specifically, after final irradiation, traps in these devices were identified via the current-transient method, and alteration of the trapping effects near the drain and gate could be observed, respectively, by applying different filling voltages. According to the time constant spectra (TCS) and differential amplitude spectra (DAS), six types of detrapping behaviors could be identified. When compared with the results during the pristine stage, the absolute amplitudes of the traps changed after irradiation, which indicated trap densities decreased near the drain and those increased near the gate. The observed changes in the trapping behaviors are consistent with the changes in the electrical properties. To identify the activation energies and locations of traps, the current-transient response was measured at various temperatures before and after electron irradiation. The possible reason for the increased activation energies is that electron irradiation turned the Ga vacancies that decorated the dislocations into pure dislocations and increased the barrier height.
在这项工作中，系统地研究了在 1-MeV 电子辐照下 p-GaN 栅极高电子迁移率晶体管（HEMTs）的电气特性和捕获效应的变化。当辐照通量增加时，漏源电流和栅极漏电流也随之上升，但阈值电压向负方向偏移。具体而言，在最终辐照后，通过电流瞬态方法识别了这些器件中的陷阱，并通过施加不同的充电电压观察到靠近漏极和栅极的捕获效应的变化。根据时间常数谱（TCS）和微分幅度谱（DAS），可以识别出六种去捕获行为。与原始阶段的结果相比，辐照后陷阱的绝对幅度发生了变化，这表明靠近漏极的陷阱密度减少，而靠近栅极的陷阱密度增加。观察到的捕获行为变化与电气特性的变化是一致的。为了确定陷阱的激活能和位置，在电子辐照前后在不同温度下测量了电流瞬态响应。激活能增加的可能原因是电子辐照将装饰在位错上的镓空位转变为纯位错，并增加了势垒高度。

Index Terms-Current-transient method, electron irradiation, p-GaN gate high-electron-mobility transistor (HEMT), traps.
索引词-瞬态电流法，电子辐照，p 型氮化镓门高电子迁移率晶体管（HEMT），陷阱。

I. INTRODUCTION 一. 引言

WITH the smaller size and weight of space power electronic systems, the basic characteristic requirements are gradually increasing for the power devices, such as efficiency, reliability, and controllability [1], [2], [3].

AlGaN / GaN

high-electron-mobility transistors (HEMTs) are widely used in power modules and frequency converters of terminal equipment in the aerospace and military fields [4], because of their low ON-resistance, high power density, and high-temperature resistance [5], [6], [7]. Among the available enhancement-mode solutions, p-GaN gate HEMTs have become the promising candidate devices for these application fields with their stable threshold voltage (

V_{TH}

), high reliability, and good repeatability [8], [9]. Nevertheless, the performance of GaN power HEMTs will still be affected after irradiation because of the high-density defects that exist in epitaxially grown GaN materials [10]. In the space environment, electronic devices will suffer from long-term irradiation and high radiation flux, which can accumulate nonionizing radiation damage in GaN and eventually cause displacement damage [11]. Moreover, radiation may introduce mobile charges into the material, forming external current, which will result significantly device performance degradation and reduce the reliability of electronic devices [12].
随着空间电力电子系统尺寸和重量的减小，对功率器件的基本特性要求逐渐提高，例如效率、可靠性和可控性。高电子迁移率晶体管（HEMTs）因其低导通电阻、高功率密度和高温抗性，在航空航天和军事领域的终端设备的功率模块和频率转换器中被广泛使用。在现有的增强模式解决方案中，p-GaN 栅极 HEMTs 因其稳定的阈值电压、高可靠性和良好的重复性，已成为这些应用领域的有前景的候选器件。然而，由于外延生长的 GaN 材料中存在高密度缺陷，GaN 功率 HEMTs 的性能在辐照后仍会受到影响。在太空环境中，电子设备将遭受长期辐照和高辐射通量，这可能在 GaN 中积累非电离辐射损伤，并最终导致位移损伤。此外，辐射可能会在材料中引入移动电荷，形成外部电流，这将显著降低器件性能并减少电子设备的可靠性[12]。

The irradiation of these devices in space is mainly caused by the high-energy protons and electrons that are present in the irradiation zone of the Earth. In recent years, there have been numerous reports on the effects of proton and electron irradiation on GaN-based materials [11], [13] and traditional depletion-mode

AlGaN / GaN

HEMTs [14], [15], [16]. The response of GaN to irradiation damage is related to the irradiation energy, the injection dose, the carrier density, and the impurity content of GaN, which would provide possible explanations for the discrepancies between different reports [4], [17]. Hwang et al. [15] studied four different heterojunction HEMTs under

10 - MeV

electron irradiation and proposed that the electron irradiation reduced the 2-D electron gas (2DEG) mobility in the

AlGaN / GaN / Si

heterojunction; this caused a reduction in the threshold voltages of the corresponding HEMTs. Chen and Liu [14] reported the effect of

1.8 - MeV

electron irradiation on

AlGaN / GaN

HEMTs that were treated using fluorine plasma and observed
这些设备在太空中的辐照主要是由存在于地球辐照区的高能质子和电子引起的。近年来，关于质子和电子辐照对基于氮化镓（GaN）材料的影响的报告屡见不鲜[11]，[13]，以及传统的耗尽模式

AlGaN / GaN

HEMT[14]，[15]，[16]。GaN 对辐照损伤的响应与辐照能量、注入剂量、载流子密度和 GaN 的杂质含量有关，这可能为不同报告之间的差异提供了可能的解释[4]，[17]。Hwang 等人[15]研究了四种不同的异质结 HEMT 在

10 - MeV

电子辐照下的表现，并提出电子辐照降低了

AlGaN / GaN / Si

异质结中的二维电子气（2DEG）迁移率；这导致了相应 HEMT 的阈值电压降低。Chen 和 Liu[14]报告了

1.8 - MeV

电子辐照对使用氟等离子体处理的

AlGaN / GaN

HEMT 的影响，并观察到

Fig. 1. In addition, we find that the abscissa of Fig. 2(a) should be

V_{GS} (V)

, instead of

V_{DS} (V)

. This change does not affect the content of the article because it is accepted that the transition characteristic curve is

I_{DS} (V) \sim V_{GS} (V)

. The modified figure is in the attachment named Fig. 2-correct.
图 1。此外，我们发现图 2(a)的横坐标应该是

V_{GS} (V)

，而不是

V_{DS} (V)

。这个更改不会影响文章的内容，因为过渡特性曲线被接受为

I_{DS} (V) \sim V_{GS} (V)

。修改后的图在名为 Fig. 2-correct 的附件中。
that the device saturation drain current increased significantly after irradiation. Although majority of these studies reported on the changes in the electrical properties of the devices before and after irradiation, the understanding of trapping behaviors in irradiated GaN devices remains relatively limited. The changes in electrical characteristics are attributed to the trapping behaviors exhibited. Therefore, the comparison and analysis of trapping effects become imperative to deepen our understanding of these phenomena before and after electron radiation.
在辐照后，器件的饱和漏电流显著增加。尽管大多数研究报告了辐照前后器件电气特性的变化，但对辐照后氮化镓（GaN）器件中捕获行为的理解仍然相对有限。电气特性的变化归因于所表现出的捕获行为。因此，比较和分析捕获效应变得至关重要，以加深我们对电子辐照前后这些现象的理解。

When the energy of the electrons falls below 0.87 MeV , the concentration of N vacancies exceeds that of Ga vacancies. Conversely, at an electron energy level of 1.2 MeV , the concentration of Ga vacancies surpasses that of N vacancies. When the electron energy is between 0.87 and 1.2 MeV , the change pattern of the device cannot be fully determined [18]. Therefore, we choose 1 MeV for experimentation.
当电子能量低于 0.87 MeV 时，氮空位的浓度超过镓空位的浓度。相反，在电子能量为 1.2 MeV 时，镓空位的浓度超过氮空位的浓度。当电子能量在 0.87 和 1.2 MeV 之间时，设备的变化模式无法完全确定[18]。因此，我们选择 1 MeV 进行实验。

In this work, we determine the effects of

1 - MeV

electron irradiation with different fluences that ranged from

1 \times

10^{13} {cm}^{- 2}

1 \times 10^{15} {cm}^{- 2}

p - GaN

gate

AlGaN / GaN

HEMTs. In particular, we used the current-transient method to investigate the trapping effects in HEMTs, which can characterize the traps with the electrical parameters of the electronic devices themselves. The trap-related amplitude, time constants, and energy levels can be extracted from current-transient curves, accordingly indicating the effects of irradiation on trapping behaviors. We can effectively determine the trap positions by applying different filling voltages in the current-transient method and explain the possible reasons for the alteration of electrical characteristics of HEMTs.
在这项工作中，我们确定了不同辐照通量下

1 - MeV

电子辐照对

p - GaN

栅

AlGaN / GaN

HEMT 的影响，辐照通量范围从

1 \times

10^{13} {cm}^{- 2}

到

1 \times 10^{15} {cm}^{- 2}

。特别地，我们使用电流瞬态方法研究 HEMT 中的捕获效应，该方法可以通过电子设备本身的电气参数来表征捕获。捕获相关的幅度、时间常数和能级可以从电流瞬态曲线中提取，从而指示辐照对捕获行为的影响。我们可以通过在电流瞬态方法中施加不同的充电电压有效地确定捕获位置，并解释 HEMT 电气特性变化的可能原因。

II. EXPERIMENTAL DETAILS II. 实验细节

The devices under investigation were 15 EPC2007C transistors, which are enhancement-mode GaN power devices with Schottky p-GaN gate structures [19]. As shown in Fig. 1, the epitaxial structure of these devices consists of a

\sim 70 - nm

p - GaN

cap layer, a

\sim 13 - nm

AlGaN barrier layer, a

\sim 2 - μ m

GaN buffer layer, and a

\sim 550 - μ m Si

substrate.
所调查的设备是 15 个 EPC2007C 晶体管，这些是具有肖特基 p-GaN 栅极结构的增强型 GaN 功率器件[19]。如图 1 所示，这些设备的外延结构由

\sim 70 - nm

p - GaN

盖层、

\sim 13 - nm

AlGaN 障碍层、

\sim 2 - μ m

GaN 缓冲层和

\sim 550 - μ m Si

基底组成。

The electron irradiation procedure was performed on the 15 devices with

1 - MeV

electrons using fluences that ranged from

1 \times 10^{13} {cm}^{- 2}

1 \times 10^{15} {cm}^{- 2}

at room temperature. The total dose received by these devices was

1.61 \times 10^{15} {cm}^{- 2}

and the electron dose rate was kept constant at

10^{11} {cm}^{- 2} \cdot s^{- 1}

电子辐照程序在 15 个设备上进行，使用的电子流量范围从

1 \times 10^{13} {cm}^{- 2}

到

1 \times 10^{15} {cm}^{- 2}

，辐照时的温度为室温。这些设备接收到的总剂量为

1.61 \times 10^{15} {cm}^{- 2}

，电子剂量率保持在恒定的

10^{11} {cm}^{- 2} \cdot s^{- 1}

。

Fig. 2. Changes in the (a) transfer curves, (b) output curves, and © gate characteristics (

I_{G S} - V_{G S}

) curves of the HEMTs with respect to electron irradiation fluences ranging from

10^{13} {cm}^{- 2}

10^{15} / {cm}^{- 2}

. The inset diagram in (a) depicts the reverse drift of the threshold voltage. The inset diagram in © depicts the equivalent circuit of the gate.
图 2. HEMT 在电子辐照通量从

10^{13} {cm}^{- 2}

到

10^{15} / {cm}^{- 2}

变化时的(a) 转移曲线，(b) 输出曲线和(c) 门特性曲线（

I_{G S} - V_{G S}

）。(a)中的插图描绘了阈值电压的反向漂移。(c)中的插图描绘了门的等效电路。
and

10^{12} {cm}^{- 2} \cdot s^{- 1}

. The irradiation process was carried out in stages with the device terminals being grounded [20]. The electron beam was turned off during each measurement, and the devices were stored at room temperature for more than 30 min to ensure stable device performance [14]. After each round of irradiation, the electrical properties of these devices were characterized using a semiconductor parameter analyzer (Keithley 4200 A ) under dc (direct current). Additionally, the drain-source current transients of the devices were measured using the current-transient method [16], [21], along with their time constant spectra (TCS) and differential amplitude spectra (DAS) [22], to investigate the trapping behaviors that occurred before and after final electron irradiation.
和

10^{12} {cm}^{- 2} \cdot s^{- 1}

。辐照过程分阶段进行，设备端子接地[20]。在每次测量期间，电子束被关闭，设备在室温下存放超过 30 分钟，以确保设备性能稳定[14]。每轮辐照后，使用半导体参数分析仪（Keithley 4200 A）在直流（dc）下对这些设备的电气特性进行表征。此外，使用电流瞬态法[16]，[21]测量设备的漏源电流瞬态，以及它们的时间常数谱（TCS）和差分幅度谱（DAS）[22]，以研究最终电子辐照前后发生的捕获行为。

III. RESULTS AND Discussion
A. Transfer, Output, and Gate Characteristics Test
III. 结果与讨论 A. 转移、输出和门特性测试

The transfer and output characteristic curves of the devices after irradiation are shown in Fig. 2(a) and (b), respectively. All samples exhibit almost the same transfer current-voltage

(I - V)

and output curves in the preirradiation case and show similar shift behaviors in the postirradiation case. Specifically, Fig. 2(a) shows that

V_{TH}

drifts slightly toward the negative direction after irradiation, and Fig. 2(b) clearly shows that the saturated drain-source current (

I_{DS}

) increases with increasing fluence. After irradiation with a dose of

1.61 \times 10^{15} {cm}^{- 2}

, the shift of

V_{TH}

was

7.8 %

and the increase of

I_{DS}

was

18.2 %

. The shift in

V_{TH}

hardly has any effect on

I_{DS}

under higher gate-source voltage (

V_{GS}

) [23]. Chen and Liu [14] concluded that the increase in

I_{DS}

could be attributed to increased electron mobility after irradiation. Studies have shown that the change in

V_{TH}

is related to the increase in the positive charge and the reduction in the negative charge in the AlGaN layer [24], [25]. In general, the electrical properties of these devices were improved after irradiation, and this improvement could be ascribed to the reduced trap densities at the AlGaN barrier layer and the GaN buffer [16].
设备在辐照后的传输和输出特性曲线分别如图 2(a)和(b)所示。所有样品在辐照前的传输电流-电压曲线几乎相同，而在辐照后则表现出类似的偏移行为。具体而言，图 2(a)显示辐照后

V_{TH}

略微向负方向漂移，图 2(b)清楚地显示饱和漏源电流（

I_{DS}

）随着辐照剂量的增加而增加。在剂量为

1.61 \times 10^{15} {cm}^{- 2}

的辐照后，

V_{TH}

的偏移为

7.8 %

，而

I_{DS}

的增加为

18.2 %

。在较高的栅源电压（

V_{GS}

）下，

V_{TH}

的偏移对

I_{DS}

几乎没有影响[23]。陈和刘[14]得出结论，

I_{DS}

的增加可以归因于辐照后电子迁移率的提高。研究表明，

V_{TH}

的变化与 AlGaN 层中正电荷的增加和负电荷的减少有关[24]，[25]。一般来说，这些器件的电气特性在辐照后得到了改善，这种改善可以归因于 AlGaN 势垒层和 GaN 缓冲层中陷阱密度的降低[16]。

Fig. 3. Illustration of the test waveforms used for the pulsed

I - V

transfer characteristics with the (a) quasi static drain bias voltage and © quasi static gate bias voltage. Pulsed

I - V

transfer characteristic curves measured under different values of (b)

V_{DSQ}

and (d)

V_{GSQ}

.
图 3. 用于脉冲

I - V

传输特性的测试波形示意图，其中(a)为准静态漏极偏置电压，(c)为准静态栅极偏置电压。在不同值下测量的脉冲

I - V

传输特性曲线，(b)为

V_{DSQ}

，(d)为

V_{GSQ}

。

Fig. 2© shows that the gate leakage current (

I_{GS}

) increases by nearly an order of magnitude (

109.6 %

) when the electron fluence reaches

10^{15} {cm}^{- 2}

. The exponential rise in

I_{GS}

versus the

V_{GS}

shown in Fig. 2© indicates the presence of a trap-related current conduction mechanism. When

V_{GS}

exceeds

V_{TH}, I_{GS}

is limited by the Schottky junction (

J_{S}

) [26]. The rise in

I_{GS}

with increasing fluence can be attributed to lowering of the barrier height of the gate metal/p-GaN junction, which indicates that the increase of trap densities near the gate raised the probability of assisted tunneling [27]. When

V_{GS}

is less than 0 V or when the forward bias is low, the surface current then plays a major role in

I_{GS}

. One of the possible mechanisms for surface current is 2-D variable-range hopping (2D-VRH) assisted by a high-density surface electronic state in AlGaN [26]. By considering deep levels in AlGaN , it is likely that some of the surface hopping electrons are trapped by the deep levels. The decrease of trap densities reduces the possibility of electron capture by the deep traps, resulting in increase in

I_{GS}

[28]. The specific details will be given in the subsequent sections.
图 2©显示，当电子通量达到

10^{15} {cm}^{- 2}

时，栅漏电流（

I_{GS}

）增加了近一个数量级（

109.6 %

）。图 2©中显示的

I_{GS}

与

V_{GS}

的指数上升表明存在与陷阱相关的电流导电机制。当

V_{GS}

超过

V_{TH}, I_{GS}

时，受肖特基结（

J_{S}

）的限制[26]。随着通量的增加，

I_{GS}

的上升可以归因于栅金属/p-GaN 结的势垒高度降低，这表明栅附近陷阱密度的增加提高了辅助隧穿的概率[27]。当

V_{GS}

小于 0 V 或当正向偏置较低时，表面电流在

I_{GS}

中起主要作用。表面电流的一个可能机制是由 AlGaN 中高密度表面电子态辅助的二维可变范围跳跃（2D-VRH）[26]。考虑到 AlGaN 中的深能级，某些表面跳跃电子可能被深能级捕获。陷阱密度的减少降低了电子被深陷阱捕获的可能性，从而导致

I_{GS}

的增加[28]。具体细节将在后面的部分中提供。

B. Pulsed Current-Voltage Characteristics
B. 脉冲电流-电压特性

To verify the presence of the traps and further analyze the effects of the irradiation, pulsed current-voltage characterization was performed on unaged samples and irradiated samples at different quiescent bias points. Fig. 3(a) and © shows the testing waveforms of the pulsed

I - V

transfer characterizations. The entire pulse period was 50 ms , and the measurement stage was set to have a fixed pulsewidth of

500 μ s

. The impact of the measurement voltage on the trapping effect can be ignored because of the low duty cycle [16]. To ensure that the device was in the same initial condition after each detrapping transient measurement, it was recovered completely by shining a

365 - nm

ultraviolet light of 1 W for 30 s [22], [29].
为了验证陷阱的存在并进一步分析辐照的影响，对未老化样品和在不同静态偏置点下的辐照样品进行了脉冲电流-电压特性测试。图 3(a)和(c)显示了脉冲

I - V

传输特性的测试波形。整个脉冲周期为 50 毫秒，测量阶段设置为固定脉冲宽度

500 μ s

。由于占空比低，测量电压对捕获效应的影响可以忽略[16]。为了确保每次去捕获瞬态测量后设备处于相同的初始状态，通过照射 1 W 的

365 - nm

紫外光 30 秒使其完全恢复[22]，[29]。

Because the electron trapping during the filling process at

(V_{GSQ}, V_{DSQ}) = (0, 0 V)

can be negligible, the alteration of

I_{DS}

由于在填充过程中

(V_{GSQ}, V_{DSQ}) = (0, 0 V)

的电子捕获可以忽略不计，因此

I_{DS}

的变化

Fig. 4. Biasing sequences of detrapping transient after a (a) certain drain filling voltage and © certain gate filling voltage. Schematics of the electron flow under the condition that (b)

(V_{GF}, V_{DF}) = (0, 25 V)

and (d)

(V_{GF}, V_{DF}) = (5, 0 V)

.
图 4. 在(a)某一漏极充电电压和(c)某一栅极充电电压下，去捕获瞬态的偏置序列。电子流的示意图在(b)

(V_{GF}, V_{DF}) = (0, 25 V)

和(d)

(V_{GF}, V_{DF}) = (5, 0 V)

的条件下。
and

V_{TH}

before and after irradiation is consistent with Fig. 2 [23]. Fig. 3(b) presents a decrease of

I_{DS}

V_{DSQ}

increases from 0 to 25 V , and this property is related to the electron trapping effect near the drain. The drain-induced

V_{TH}

shift in the p-GaN HEMTs was ascribed to the charge storage model [30]. The comparison of the variations in

I_{DS}

before and after irradiation shows that

I_{DS}

decreases by

9.90 %

and

6.87 %

, respectively. The electron trapping effect still exists, but it is weakened after irradiation [16]. The irradiation has little effect on the attenuation of

I_{DS}

when the gate bias voltage is applied. Therefore, the drain traps are more sensitive to the electron irradiation than the traps below the gate. The details of the irradiation effects and the trap locations will be given in the subsequent sections.
在辐照前后

V_{TH}

与图 2 [23]一致。图 3(b)显示当

V_{DSQ}

从 0 增加到 25 V 时，

I_{DS}

减少，这一特性与靠近漏极的电子捕获效应有关。p-GaN HEMTs 中漏极引起的

V_{TH}

偏移归因于电荷存储模型[30]。辐照前后

I_{DS}

变化的比较显示，

I_{DS}

分别减少了

9.90 %

和

6.87 %

。电子捕获效应仍然存在，但在辐照后减弱[16]。当施加栅极偏置电压时，辐照对

I_{DS}

的衰减影响很小。因此，漏极陷阱对电子辐照的敏感性高于栅极下的陷阱。辐照效应和陷阱位置的详细信息将在后续部分中给出。

C. Comparison of the Detrapping Transients
C. 去捕获瞬态的比较

To gain further understanding of the effects of electron irradiation on p-GaN gate HEMTs, we continued our study of the changes in the traps using the current-transient method. Detailed information about the measurement methods used can be found in [21] and [22]. To obtain the current-transient response, it is necessary to apply an additional large electrical stress before the measurement process to ensure that the traps are fully filled and then switch rapidly to a small measurement bias voltage to monitor the electrons release process from the traps. The bias sequences used in the experiment are shown in Fig. 4(a) and ©. As shown in Fig. 4(b) and (d), during the filling process,

(V_{GF}, V_{D F}) = (0, 25 V)

and

(V_{GF}, V_{DF}) = (5

, 0 V ) induced carrier trapping for 30 s , electrons will fill the traps near the drain and gate, respectively [23], [31]. Subsequently, we monitored the recovery current under conditions of

(V_{GM}, V_{DM}) = (2.2, 0.5 V)

V_{GM}

needs to ensure that the 2DEG channel is turned on, and

V_{DM}

is low enough, so that the electron filling can be ignored during the measurement process [22].
为了进一步了解电子辐照对 p-GaN 栅极 HEMT 的影响，我们继续研究使用电流瞬态法对陷阱变化的分析。关于所使用的测量方法的详细信息可以在[21]和[22]中找到。为了获得电流瞬态响应，在测量过程之前需要施加额外的大电压应力，以确保陷阱完全充满，然后迅速切换到小的测量偏置电压，以监测电子从陷阱释放的过程。实验中使用的偏置序列如图 4(a)和(c)所示。如图 4(b)和(d)所示，在充填过程中，

(V_{GF}, V_{D F}) = (0, 25 V)

和

(V_{GF}, V_{DF}) = (5

，0 V 诱导载流子捕获 30 秒，电子将分别填充靠近漏极和栅极的陷阱[23]，[31]。随后，我们在

(V_{GM}, V_{DM}) = (2.2, 0.5 V)

条件下监测恢复电流。

V_{GM}

需要确保 2DEG 通道已开启，并且

V_{DM}

足够低，以便在测量过程中可以忽略电子充填[22]。

Fig. 5 presents the comparisons of the detrapping effects before and after electron irradiation at room temperature under
图 5 展示了在室温下电子辐照前后去捕获效应的比较。

Fig. 5. Comparison of charge detrapping effects before and after electron irradiation at a fluence of

1.61 \times 10^{15} {cm}^{- 2}

under the condition that

(V_{GF}, V_{DF}) = (0, 25 V)

. (a) Current transient curves showing the weakening in the trapping effects. (b) TCS shows the decrease in the three time constants. © Corresponding DAS. (d) Three traps obtained from the DAS before and after the electron irradiation.
图 5. 在

(V_{GF}, V_{DF}) = (0, 25 V)

条件下，电子辐照前后以

1.61 \times 10^{15} {cm}^{- 2}

的剂量比较电荷去捕获效应。(a) 显示捕获效应减弱的电流瞬态曲线。(b) TCS 显示三个时间常数的减少。(c) 相应的 DAS。(d) 电子辐照前后从 DAS 获得的三个陷阱。
the bias conditions of

(V_{GF}, V_{DF}) = (0, 25 V)

. To enable comparison of the current variations directly, we normalized the measured current transients [16], [23]. As shown in Fig. 5(a), after electron irradiation, the total variation in the drain-source current transients of the samples decreases; this indicates that the charge trapping effects near the drain are weakened. Bayesian deconvolution was performed on the current transient curves to obtain the TCS, as shown in Fig. 5(b). According to the TCS, three types of detrapping behaviors can be identified, and they are named DP1-DP3. The time constants corresponding to the peaks in the TCS are basically the same, so we considered that the same traps play roles before and after irradiation, without the emergence of new trap types [21], [22]. Since the TCS only reflects the relative amplitudes of the peak and does not take into account the average strength on both sides of the peak, Fig. 5(b) cannot represent the variations of trap densities accurately. The relative amplitude values in Fig. 5(b) were accumulated and the DAS was obtained via first-order derivation, with results as shown in Fig. 5©. To compare the variations of absolute amplitudes directly, the DAS shows the absolute amplitudes of these three detrapping behaviors. Fig. 5(d) shows the amplitude values that were read out from Fig. 5©. The sum of the three amplitude values is consistent with the total variation in the current transient curves shown in Fig. 5(a) [24]. As shown in Fig. 5(d), the amplitudes of three detrapping behaviors all decreased after irradiation, thus indicating a reduction in the trapping densities of these three traps. We suggest that these variations in the trap densities can be attributed to the relaxation of strain in GaN following electron irradiation [16].

(V_{GF}, V_{DF}) = (0, 25 V)

的偏置条件。为了直接比较电流变化，我们对测量的电流瞬态进行了归一化[16]，[23]。如图 5(a)所示，电子辐照后，样品的漏源电流瞬态的总变化减小；这表明靠近漏极的电荷捕获效应减弱。对电流瞬态曲线进行了贝叶斯解卷积，以获得 TCS，如图 5(b)所示。根据 TCS，可以识别出三种去捕获行为，分别命名为 DP1-DP3。与 TCS 中峰值对应的时间常数基本相同，因此我们认为在辐照前后相同的陷阱发挥作用，没有出现新的陷阱类型[21]，[22]。由于 TCS 仅反映峰值的相对幅度，而未考虑峰值两侧的平均强度，因此图 5(b)无法准确表示陷阱密度的变化。图 5(b)中的相对幅度值被累积，并通过一阶导数获得 DAS，结果如图 5(c)所示。为了直接比较绝对振幅的变化，DAS 显示了这三种去捕获行为的绝对振幅。图 5(d) 显示了从图 5(c) 读取的振幅值。这三个振幅值的总和与图 5(a) 中显示的电流瞬态曲线的总变化一致[24]。如图 5(d) 所示，三种去捕获行为的振幅在辐照后均有所下降，这表明这三种陷阱的捕获密度降低。我们认为，这些捕获密度的变化可以归因于电子辐照后 GaN 中应变的松弛[16]。

Besides, the comparisons of the detrapping effects under the bias conditions of

(V_{GF}, V_{DF}) = (5, 0 V)

are illustrated in Fig. 6, and the specific process is consistent with Fig. 5. As shown in Fig. 6(a), after electron irradiation, the total variation in the drain-source current transient of the samples
此外，图 6 展示了在

(V_{GF}, V_{DF}) = (5, 0 V)

偏置条件下去捕获效应的比较，具体过程与图 5 一致。如图 6(a)所示，电子辐照后，样品的漏源电流瞬态总变化。

Fig. 6. Comparison of charge detrapping effects before and after electron irradiation under the condition that

(V_{GF}, V_{DF}) = (5, 0 V)

. (a) Current transient curves, showing the enhancement in the trapping effects. (b) Corresponding TCS. © Corresponding DAS. (d) Three traps obtained from the DAS before and after the electron irradiation.
图 6. 在

(V_{GF}, V_{DF}) = (5, 0 V)

条件下电子辐照前后电荷去捕获效应的比较。(a) 电流瞬态曲线，显示捕获效应的增强。(b) 相应的 TCS。(c) 相应的 DAS。(d) 电子辐照前后从 DAS 获得的三个陷阱。
increases when the condition that

(V_{GF}, V_{DF}) = (5, 0 V)

is applied. According to the TCS in Fig. 6(b), three types of detrapping behaviors can be identified, and they are named DP4-DP6. As shown in Fig. 6© and (d), the amplitudes of the detrapping behaviors near the gate increase after irradiation, indicating an increase in the trapping densities. We suggest that high-energy electrons excited by irradiation create defects near the metal/p-GaN interface by colliding with the lattice, which may introduce trap-assisted tunneling and the increase in

I_{GS} [17]

.
在施加条件

(V_{GF}, V_{DF}) = (5, 0 V)

时，增加。根据图 6(b)中的 TCS，可以识别出三种去捕获行为，分别命名为 DP4-DP6。如图 6(c)和(d)所示，辐照后靠近栅极的去捕获行为的幅度增加，表明捕获密度增加。我们建议，辐照激发的高能电子通过与晶格碰撞在金属/p-GaN 界面附近产生缺陷，这可能引入陷阱辅助隧穿并增加

I_{GS} [17]

。

D. Identification of the Energy Levels
D. 能级的识别

To study the specific effects of each trap on the electrical properties, we need to identify the

E_{A}

values and locations of DP1-DP6. The current-transient response was measured at various temperatures, and the TCS is shown in Fig. 7(a) and ©, where

(V_{GF}, V_{DF}) = (0, 25 V)

and

(5

E_{A}

values of the six traps were calculated using the Arrhenius equation [21], [22], with results as shown in Fig. 7(b) and (d). Since the activation energy of the trap is also different, the six traps can be identified as different traps. Fig. 8 shows the trap positions, energy levels, and the variations of trap densities reflected by the amplitudes before and after irradiation.
为了研究每个陷阱对电气特性的具体影响，我们需要确定 DP1-DP6 的

E_{A}

值和位置。在不同温度下测量了电流瞬态响应，TCS 如图 7(a)和(c)所示，其中

(V_{GF}, V_{DF}) = (0, 25 V)

和

(5

，分别为 0 V。从图 7(a)和(c)可以看出，陷阱填充机制和时间常数是不同的。六个陷阱的

E_{A}

值是使用 Arrhenius 方程[21]，[22]计算得出的，结果如图 7(b)和(d)所示。由于陷阱的激活能也不同，这六个陷阱可以被识别为不同的陷阱。图 8 显示了陷阱的位置、能级以及辐照前后反映的陷阱密度的变化。

The results show that the DP1 and DP4 fitted

E_{A}

values are consistent before and after electron irradiation, which indicates that the trap levels of DP1 and DP4 remain unchanged. Specifically, DP1 is identified at an

E_{A}

of 0.31 eV . The trapping behavior in a GaN layer with a similar time constant was also reported in [32], [33], and [33], and thus, DP1 is confirmed to be in the GaN buffer layer. The other traps’ fitted

E_{A}

values increase when compared with the values before irradiation, indicating that irradiation deepens the trap energy levels in these devices. Moreover, the variations of DP2 and DP3 energy levels near the drain are the same, as well as DP5 and DP6 near
结果表明，DP1 和 DP4 的拟合

E_{A}

值在电子辐照前后是一致的，这表明 DP1 和 DP4 的陷阱能级保持不变。具体而言，DP1 的

E_{A}

被确定为 0.31 eV。在 [32]、[33] 和 [33] 中也报告了具有类似时间常数的 GaN 层中的捕获行为，因此确认 DP1 位于 GaN 缓冲层中。与辐照前的值相比，其他陷阱的拟合

E_{A}

值增加，表明辐照加深了这些器件中的陷阱能级。此外，DP2 和 DP3 在漏极附近的能级变化相同，DP5 和 DP6 也在附近。

Fig. 7. Experimental results for detrapping at different temperatures after electron irradiation with a fluence of

1.61 \times 10^{15} {cm}^{- 2}

. (a) TCS and (b) energy levels corresponding to DP1-DP3 at

(V_{GF}, V_{DF}) = (0

(V_{GF}, V_{DF}) = (5, 0 V)

.
图 7. 在不同温度下电子辐照后去捕获的实验结果，辐照剂量为

1.61 \times 10^{15} {cm}^{- 2}

。(a) TCS 和(b) 对应于 DP1-DP3 的能级在

(V_{GF}, V_{DF}) = (0

(V_{GF}, V_{DF}) = (5, 0 V)

。

Fig. 8. Band diagram of

p - G a N / A I G a N / G a N

gate-stack after electron irradiation.
图 8. 电子辐照后

p - G a N / A I G a N / G a N

门堆的能带图。
the gate. The possible reason for the deepening of the energy levels is as follows. During irradiation, electrons are injected into the lattice and collide with the atoms, thus causing a quantity of the Ga atoms to be scattered from the lattice positions to the interstitial positions to form interstitial Ga

({Ga}_{i})

and leave Ga vacancies

(V_{Ga}) . G a_{i}

can then passivate a

V_{Ga}

decorated dislocation

(V_{Ga} - D L)

to form a pure dislocation (pure DL). The transition from

V_{Ga} - D L

to pure DL modulates the energy band, and this modulation may exist in p-GaN and AlGaN. As shown in Fig. 8, before irradiation, the electrons can be trapped and released by these traps with low activation energies through

V_{Ga} - D L s

. After irradiation, the state of the pure DL is deeper than that of

V_{Ga} - D L

, and the electrons then require more energy to be released from the electron traps, and the trap energy levels become deeper as a result [27], [34]. Traps similar to DP2 and DP3 can be found in [15] and [35], respectively. DP2 and DP3 are considered to be located within the AlGaN layer, and DP5 and DP6 are located within the p-GaN layer. DP4 was identified at the 0.40 eV level near the gate, because its

E_{A}

remains unchanged, DP4 is considered to be located at the metal/p-GaN interface close to the gate.
门。能级加深的可能原因如下。在辐照过程中，电子被注入到晶格中并与原子碰撞，从而导致一些 Ga 原子从晶格位置散射到间隙位置，形成间隙 Ga

({Ga}_{i})

并留下 Ga 空位

(V_{Ga}) . G a_{i}

，然后可以钝化一个

V_{Ga}

装饰的位错

(V_{Ga} - D L)

，形成纯位错（纯 DL）。从

V_{Ga} - D L

到纯 DL 的过渡调制了能带，这种调制可能存在于 p-GaN 和 AlGaN 中。如图 8 所示，在辐照之前，电子可以通过

V_{Ga} - D L s

被这些低激活能的陷阱捕获和释放。辐照后，纯 DL 的状态比

V_{Ga} - D L

更深，电子因此需要更多的能量才能从电子陷阱中释放出来，陷阱能级因此变得更深 [27]，[34]。类似于 DP2 和 DP3 的陷阱分别可以在[15]和[35]中找到。DP2 和 DP3 被认为位于 AlGaN 层内，而 DP5 和 DP6 位于 p-GaN 层内。DP4 在 0 处被识别。在栅极附近的 40 eV 能级，因为其

E_{A}

保持不变，DP4 被认为位于靠近栅极的金属/p-GaN 界面。

The changes in the electrical characteristics of the HEMTs before and after irradiation are closely related to the changes in trap densities. The collisions of the incident electrons in the lattice can produce quantities of electron-hole pairs. The electrons can be trapped, whereas the holes are relatively immobile. The trap densities of DP2 and DP3 in the AlGaN layer decrease and the negative electric center formed by the trapped electrons is reduced, which means that the number of negative charges in the AlGaN layer decreases and the threshold voltage drifts negatively [24]. In addition, the reason for the increase in

I_{DS}

is that the effects of Coulomb scattering on the electron mobility are reduced, which means that the mobility of the 2DEG increases [20]. The

E_{A}

values of DP2 and DP3 increase after irradiation, and the deep-level traps are more likely to capture electrons and these electrons are also less likely to escape [20]. However, an increase in

I_{DS}

shows that the effect of the trap density on the performance takes precedence over the deepening of the energy levels. The increase of the trap density of DP4 uprises the probability of assisted tunneling, which is equivalent to reducing the Schottky barrier height [24]. The decrease of trap density of DP3 reduces the possibility of electron capture by the deep traps, resulting in increase in the surface current and

I_{GS}

[28].
HEMTs 在辐照前后的电特性变化与陷阱密度的变化密切相关。入射电子在晶格中的碰撞可以产生大量的电子-空穴对。电子可以被捕获，而空穴则相对不动。AlGaN 层中 DP2 和 DP3 的陷阱密度降低，被捕获电子形成的负电中心减少，这意味着 AlGaN 层中的负电荷数量减少，阈值电压向负方向漂移。此外，

I_{DS}

增加的原因是库仑散射对电子迁移率的影响减小，这意味着 2DEG 的迁移率增加。辐照后，DP2 和 DP3 的

E_{A}

值增加，深能级陷阱更容易捕获电子，这些电子也更不容易逃逸。然而，

I_{DS}

的增加表明，陷阱密度对性能的影响优先于能级的加深。 DP4 的陷阱密度增加提高了辅助隧穿的概率，这相当于降低了肖特基势垒高度[24]。DP3 的陷阱密度降低减少了深陷阱对电子捕获的可能性，从而导致表面电流和

I_{GS}

增加[28]。

IV. CONCLUSION 四. 结论

In this article, we have reported on the electrical characteristics and trapping effects of electron irradiation on p-GaN gate-based HEMTs in detail. To determine the changes in the device electrical properties, current-voltage measurements were performed before and after irradiation. Particularly, we identified six trap types in the HEMTs using the current-transient method and the DAS and also investigated the variations in these traps after the final electron irradiation. The trap densities in the AlGaN layer were reduced, and thus, the electron mobility was increased, which may be the reason for the negative drift of threshold voltage and the increase in

I_{Ds}

. Furthermore, the reduction of trap densities also uprose the surface current, and the increased trap densities of Schottky junction increased the probability of assisted tunneling, and those resulted in an increase in the gate leakage current. Electron irradiation turned the Ga vacancies that decorated the dislocations into pure dislocations and uprose the barrier height, which increased the activation energies of four traps. This article provides a reference value for the improvement of manufacturing process and application of

p - GaN

gate HEMTs in the aerospace field.
在本文中，我们详细报告了电子辐照对 p-GaN 栅极 HEMT 的电气特性和捕获效应。为了确定器件电气特性的变化，在辐照前后进行了电流-电压测量。特别地，我们使用电流瞬态方法和 DAS 在 HEMT 中识别了六种捕获类型，并调查了最终电子辐照后这些捕获的变化。AlGaN 层中的捕获密度降低，因此电子迁移率增加，这可能是阈值电压负漂移和

I_{Ds}

增加的原因。此外，捕获密度的降低也提高了表面电流，而肖特基结的捕获密度增加了辅助隧穿的概率，从而导致栅极漏电流增加。电子辐照将装饰位错的镓空位转变为纯位错，并提高了势垒高度，从而增加了四个捕获的激活能。本文为

p - GaN

门 HEMTs 在航空航天领域的制造工艺改进和应用提供了参考价值。

REFERENCES 参考文献

[1] G. Dutta, N. DasGupta, and A. DasGupta, “Gate leakage mechanisms in AlInN/GaN and AlGaN/GaN MIS-HEMTs and its modeling,” IEEE Trans. Electron Devices, vol. 64, no. 9, pp. 3609-3615, Sep. 2017, doi: 10.1109/TED.2017.2723932.
G. Dutta, N. DasGupta 和 A. DasGupta，“AlInN/GaN 和 AlGaN/GaN MIS-HEMT 中的栅漏机制及其建模，”IEEE 电子器件汇刊，卷 64，第 9 期，页 3609-3615，2017 年 9 月，doi: 10.1109/TED.2017.2723932。
[2] S. Yang et al., “Identification of trap states in p-GaN layer of a p-GaN/AlGaN/GaN power HEMT structure by deep-level transient spectroscopy,” IEEE Electron Device Lett., vol. 41, no. 5, pp. 685-688, May 2020, doi: 10.1109/LED.2020.2980150.
[2] S. Yang 等, “通过深能级瞬态光谱识别 p-GaN/AlGaN/GaN 功率 HEMT 结构中 p-GaN 层的陷阱态,” IEEE 电子器件快报, 第 41 卷, 第 5 期, 第 685-688 页, 2020 年 5 月, doi: 10.1109/LED.2020.2980150.
[3] R. R. Chaudhuri, V. Joshi, S. D. Gupta, and M. Shrivastava, “On the channel hot-electron’s interaction with C-doped GaN buffer and resultant gate degradation in AlGaN/GaN HEMTs,” IEEE Trans. Electron Devices, vol. 68, no. 10, pp. 4869-4876, Oct. 2021, doi: 10.1109/TED. 2021.3102469.
[3] R. R. Chaudhuri, V. Joshi, S. D. Gupta, 和 M. Shrivastava, “关于通道热电子与掺碳 GaN 缓冲层的相互作用及其在 AlGaN/GaN HEMTs 中的栅极退化,” IEEE 电子器件学报, 第 68 卷, 第 10 期, 第 4869-4876 页, 2021 年 10 月, doi: 10.1109/TED. 2021.3102469.
[4] S. J. Pearton, Y.-S. Hwang, and F. Ren, “Radiation effects in GaN-based high electron mobility transistors,” Jom, vol. 67, no. 7, pp. 1601-1611, 2015, doi:

10.1007 / s 11837 - 015 - 1359 - y

[4] S. J. Pearton, Y.-S. Hwang, 和 F. Ren, “基于 GaN 的高电子迁移率晶体管中的辐射效应,” Jom, 第 67 卷, 第 7 期, 页 1601-1611, 2015, doi:

10.1007 / s 11837 - 015 - 1359 - y

[5] T. Satoh, K. Osawa, and A. Nitta, “GaN HEMT for space applications,” in Proc. IEEE BiCMOS Compound Semiconductor Integr. Circuits Technol. Symp. (BCICTS), San Diego, CA, USA, Oct. 2018, pp. 136-139, doi: 10.1109/BCICTS.2018.8551070.
[5] T. Satoh, K. Osawa, 和 A. Nitta, “用于空间应用的 GaN HEMT,” 见于 IEEE BiCMOS 复合半导体集成电路技术研讨会 (BCICTS) 论文集, 美国加利福尼亚州圣地亚哥, 2018 年 10 月, 第 136-139 页, doi: 10.1109/BCICTS.2018.8551070.
[6] H.-P. Lee and C. Bayram, “Improving current ON/OFF ratio and subthreshold swing of Schottky-gate AlGaN/GaN HEMTs by postmetallization annealing,” IEEE Trans. Electron Devices, vol. 67, no. 7, pp. 2760-2764, Jul. 2020, doi: 10.1109/TED. 2020.2992014.
[6] H.-P. Lee 和 C. Bayram, “通过后金属化退火改善 Schottky 门 AlGaN/GaN HEMT 的当前开关比和亚阈值摆幅,” IEEE 电子器件学报, 第 67 卷, 第 7 期, 页 2760-2764, 2020 年 7 月, doi: 10.1109/TED.2020.2992014.
[7] X. Zheng et al., “Evidence of GaN HEMT Schottky gate degradation after gamma irradiation,” IEEE Trans. Electron Devices, vol. 66, no. 9, pp. 3784-3788, Sep. 2019, doi: 10.1109/TED.2019.2928560.
[7] X. Zheng 等, “伽马辐射后 GaN HEMT 肖特基栅极退化的证据,” IEEE 电子器件学报, 第 66 卷, 第 9 期, 页 3784-3788, 2019 年 9 月, doi: 10.1109/TED.2019.2928560.
[8] Y. Xin, W. Chen, R. Sun, X. Deng, Z. Li, and B. Zhang, “Barrier lowering-induced capacitance increase of short-channel power p-GaN HEMTs at high temperature,” IEEE Trans. Electron Devices, vol. 69, no. 3, pp. 1176-1180, Mar. 2022, doi: 10.1109/TED.2021.3139561.
[8] Y. Xin, W. Chen, R. Sun, X. Deng, Z. Li, 和 B. Zhang, “高温下短通道功率 p-GaN HEMT 的势垒降低引起的电容增加,” IEEE 电子器件学报, 第 69 卷, 第 3 期, 页 1176-1180, 2022 年 3 月, doi: 10.1109/TED.2021.3139561.
[9] J. Chen et al., “The device instability of p-GaN gate HEMTs induced by self-heating effect investigated by on-state drain current injection (DCI) technique,” IEEE Trans. Electron Devices, vol. 69, no. 10, pp. 5496-5502, Oct. 2022, doi: 10.1109/TED.2022.3200301.
[9] J. Chen 等, “自加热效应引起的 p-GaN 门 HEMT 设备不稳定性通过开态漏电流注入 (DCI) 技术进行研究,” IEEE 电子器件汇刊, 第 69 卷, 第 10 期, 第 5496-5502 页, 2022 年 10 月, doi: 10.1109/TED.2022.3200301.
[10] D. Zhang et al., “Reliability improvement of GaN devices on freestanding GaN substrates,” IEEE Trans. Electron Devices, vol. 65, no. 8, pp. 3379-3387, Aug. 2018, doi: 10.1109/TED. 2018.2848971.
[10] D. Zhang 等, “在独立 GaN 基板上提高 GaN 器件的可靠性,” IEEE 电子器件汇刊, 第 65 卷, 第 8 期, 第 3379-3387 页, 2018 年 8 月, doi: 10.1109/TED.2018.2848971.
[11] A. Y. Polyakov, S. J. Pearton, P. Frenzer, F. Ren, L. Liu, and J. Kim, “Radiation effects in GaN materials and devices,” J. Mater. Chem. C, vol. 1, no. 5, pp. 877-887, 2013, doi: 10.1039/c2tc00039c.
[11] A. Y. Polyakov, S. J. Pearton, P. Frenzer, F. Ren, L. Liu, 和 J. Kim, “GaN 材料和器件中的辐射效应,” J. Mater. Chem. C, 第 1 卷, 第 5 期, 页 877-887, 2013, doi: 10.1039/c2tc00039c.
[12] S. J. Pearton et al., “Review-Radiation damage in wide and ultra-wide bandgap semiconductors,” ECS J. Solid State Sci. Technol., vol. 10, no. 5, May 2021, Art. no. 055008, doi: 10.1149/2162-8777/abfc23.
[12] S. J. Pearton 等, “综述-宽带和超宽带隙半导体中的辐射损伤,” ECS 固态科学与技术杂志, 第 10 卷, 第 5 期, 2021 年 5 月, 文章编号 055008, doi: 10.1149/2162-8777/abfc23.
[13] T. T. Duc, G. Pozina, N. T. Son, E. Janzén, T. Ohshima, and C. Hemmingsson, “Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy,” Appl. Phys. Lett., vol. 105, no. 10, Sep. 2014, Art. no. 102103, doi: 10.1063/1.4895390.
[13] T. T. Duc, G. Pozina, N. T. Son, E. Janzén, T. Ohshima, 和 C. Hemmingsson, “通过卤化物蒸气相外延生长的 GaN 大块材料中的辐射诱导缺陷,” 应用物理快报, 第 105 卷, 第 10 期, 2014 年 9 月, 文章编号 102103, doi: 10.1063/1.4895390.
[14] C. Chen and X. Z. Liu, “Effects of low-energy electron irradiation on enhancement-mode AlGaN/GaN high-electron-mobility transistors,” Adv. Mater. Res., vols. 774-776, pp. 876-880, Sep. 2013, doi: 10.4028/www.scientific.net/amr.774-776.876.
[14] C. Chen 和 X. Z. Liu, “低能电子辐照对增强模式 AlGaN/GaN 高电子迁移率晶体管的影响,” Adv. Mater. Res., 卷 774-776, 页 876-880, 2013 年 9 月, doi: 10.4028/www.scientific.net/amr.774-776.876.
[15] Y.-S. Hwang et al., “Effect of electron irradiation on

AlGaN / GaN

and InAlN/GaN heterojunctions,” J. Vac. Sci. Technol. B, Nanotechnol. Microelectron., Mater., Process., Meas., Phenomena, vol. 31, no. 2, Mar. 2013, Art. no. 022206, doi: 10.1116/1.4795210.
[15] Y.-S. Hwang 等, “电子辐照对

AlGaN / GaN

和 InAlN/GaN 异质结的影响,” 真空科学与技术 B, 纳米技术与微电子, 材料, 过程, 测量, 现象, 第 31 卷, 第 2 期, 2013 年 3 月, 文章编号 022206, doi: 10.1116/1.4795210.
[16] S. Pan et al., “Analysis of the effects of high-energy electron irradiation of GaN high-electron-mobility transistors using the voltage-transient method,” IEEE Trans. Electron Devices, vol. 68, no. 8, pp. 3968-3973, Aug. 2021, doi: 10.1109/TED.2021.3089449.
[16] S. Pan 等, “使用电压瞬态法分析高能电子辐照对 GaN 高电子迁移率晶体管的影响,” IEEE 电子器件学报, 第 68 卷, 第 8 期, 第 3968-3973 页, 2021 年 8 月, doi: 10.1109/TED.2021.3089449.
[17] S. J. Pearton, F. Ren, E. Patrick, M. E. Law, and A. Y. Polyakov, “Review-Ionizing radiation damage effects on GaN devices,” ECS J. Solid State Sci. Technol., vol. 5, no. 2, pp. 35-60, 2016, doi: 10.1149/2.0251602jss
[17] S. J. Pearton, F. Ren, E. Patrick, M. E. Law, 和 A. Y. Polyakov, “综述-电离辐射对 GaN 器件的损伤影响,” ECS J. Solid State Sci. Technol., vol. 5, no. 2, pp. 35-60, 2016, doi: 10.1149/2.0251602jss
[18] J. W. McClory, J. C. Petrosky, J. M. Sattler, and T. A. Jarzen, “An analysis of the effects of low-energy electron irradiation of AlGaN/GaN HFETs,” IEEE Trans. Nucl. Sci., vol. 54, no. 6, pp. 1946-1952, Dec. 2007, doi: 10.1109/TNS.2007.910121.
[18] J. W. McClory, J. C. Petrosky, J. M. Sattler, 和 T. A. Jarzen, “低能电子辐照对 AlGaN/GaN HFETs 影响的分析,” IEEE 核科学汇刊, 第 54 卷, 第 6 期, 页 1946-1952, 2007 年 12 月, doi: 10.1109/TNS.2007.910121.
[19] Efficient Power Conversion. (2013). EPC2007C-Enhancement Mode Power Transistor. [Online]. Available: https://epc-co.com/epc/Portals/0/ epc/documents/datasheets/EPC2007C_datasheet.pdf
[19] 高效电源转换。 (2013)。EPC2007C-增强模式功率晶体管。 [在线]。可用：https://epc-co.com/epc/Portals/0/ epc/documents/datasheets/EPC2007C_datasheet.pdf
[20] P. Wang et al., “Investigation of trapping effects in Schottky lightly doped p-GaN gate stack under

γ

-ray irradiation,” Appl. Phys. Lett., vol. 121, no. 14, Oct. 2022, Art. no. 143501, doi: 10.1063/5.0094090.
[20] P. Wang 等, “在

γ

-射线辐照下对轻掺杂 p-GaN 闸极堆栈中捕获效应的研究,” 应用物理快报, 第 121 卷, 第 14 期, 2022 年 10 月, 文章编号 143501, doi: 10.1063/5.0094090.
[21] X. Zheng, S. Feng, Y. Gao, Y. Zhang, Y. Jia, and S. Pan, “A voltage-transient method for characterizing traps in GaN HEMTs,” Microelectron. Rel., vol. 93, pp. 57-60, Feb. 2019, doi: 10.1016/j.microrel.2018.12.009.
[21] X. Zheng, S. Feng, Y. Gao, Y. Zhang, Y. Jia, 和 S. Pan, “一种用于表征 GaN HEMT 中陷阱的电压瞬态方法,” 微电子可靠性, 第 93 卷, 第 57-60 页, 2019 年 2 月, doi: 10.1016/j.microrel.2018.12.009.
[22] X. Zheng, S. Feng, Y. Zhang, X. He, and Y. Wang, “A new differential amplitude spectrum for analyzing the trapping effect in GaN HEMTs based on the drain current transient,” IEEE Trans. Electron Devices, vol. 64, no. 4, pp. 1498-1504, Apr. 2017, doi: 10.1109/TED. 2017.2654481.
[22] X. Zheng, S. Feng, Y. Zhang, X. He, 和 Y. Wang, “一种新的差分幅度谱用于分析基于漏电流瞬态的 GaN HEMT 中的捕获效应,” IEEE 电子器件学报, 第 64 卷, 第 4 期, 第 1498-1504 页, 2017 年 4 月, doi: 10.1109/TED. 2017.2654481.
[23] S. Pan et al., “Identification of traps in p-GaN gate HEMTs during OFF-state stress by current transient method,” IEEE Trans. Electron Devices, vol. 69, no. 9, pp. 4877-4882, Sep. 2022, doi: 10.1109/TED. 2022.3193889.
[23] S. Pan 等, “通过电流瞬态方法识别 p-GaN 门 HEMT 在关态应力下的陷阱,” IEEE 电子器件学报, 第 69 卷, 第 9 期, 第 4877-4882 页, 2022 年 9 月, doi: 10.1109/TED.2022.3193889.
[24] X. Zhou et al., “Total-ionizing-dose radiation effect on dynamic threshold voltage in p-GaN gate HEMTs,” IEEE Trans. Electron Devices, vol. 70, no. 8, pp. 4081-4086, Aug. 2023, doi: 10.1109/TED.2023.3285515.
[24] X. Zhou 等, “总电离剂量辐射对 p-GaN 门 HEMT 动态阈值电压的影响,” IEEE 电子器件汇刊, 第 70 卷, 第 8 期, 第 4081-4086 页, 2023 年 8 月, doi: 10.1109/TED.2023.3285515.
[25] Z. Jiang, L. Li, C. Wang, J. Zhao, and M. Hua, “Gate-bias induced threshold voltage (VTH) instability in P-N junction/AlGaN/GaN HEMT,” IEEE Trans. Electron Devices, vol. 69, no. 7, pp. 3654-3659, Jul. 2022, doi: 10.1109/TED.2022.3177397.
[25] Z. Jiang, L. Li, C. Wang, J. Zhao, 和 M. Hua, “门偏置引起的 P-N 结/AlGaN/GaN HEMT 阈值电压 (VTH) 不稳定性,” IEEE 电子器件学报, 第 69 卷, 第 7 期, 第 3654-3659 页, 2022 年 7 月, doi: 10.1109/TED.2022.3177397.
[26] N. Xu et al., “Gate leakage mechanisms in normally off pGaN/AlGaN/GaN high electron mobility transistors,” Appl. Phys. Lett., vol. 113, no. 15, Oct. 2018, Art. no. 152104, doi: 10.1063/1.5041343.
[26] N. Xu 等, “正常关断 pGaN/AlGaN/GaN 高电子迁移率晶体管中的栅漏电机制,” 应用物理快报, 第 113 卷, 第 15 期, 2018 年 10 月, 文章编号 152104, doi: 10.1063/1.5041343.
[27] R. Sun, X. Chen, C. Liu, W. Chen, and B. Zhang, “Degradation mechanism of Schottky p-GaN gate stack in GaN power devices under neutron irradiation,” Appl. Phys. Lett., vol. 119, no. 13, Sep. 2021, Art. no. 133503, doi: 10.1063/5.0065046.
[27] R. Sun, X. Chen, C. Liu, W. Chen, 和 B. Zhang, “在中子辐照下 GaN 功率器件中 Schottky p-GaN 门堆的降解机制,” 应用物理快报, 第 119 卷, 第 13 期, 2021 年 9 月, 文章编号 133503, doi: 10.1063/5.0065046.
[28] J. Kotani, M. Tajima, S. Kasai, and T. Hashizume, “Mechanism of surface conduction in the vicinity of Schottky gates on AlGaN/GaN heterostructures,” Appl. Phys. Lett., vol. 91, no. 9, Aug. 2007, Art. no. 093501, doi: 10.1063/1.2775834.
[28] J. Kotani, M. Tajima, S. Kasai, 和 T. Hashizume, “AlGaN/GaN 异质结构中肖特基栅极附近表面导电机制,” 应用物理快报, 第 91 卷, 第 9 期, 2007 年 8 月, 文章编号 093501, doi: 10.1063/1.2775834.
[29] J. Joh and J. A. del Alamo, “A current-transient methodology for trap analysis for GaN high electron mobility transistors,” IEEE Trans. Electron Devices, vol. 58, no. 1, pp. 132-140, Jan. 2011, doi: 10.1109/TED.2010.2087339.
[29] J. Joh 和 J. A. del Alamo，“用于氮化镓高电子迁移率晶体管的陷阱分析的电流瞬态方法”，IEEE 电子器件学报，卷 58，第 1 期，页 132-140，2011 年 1 月，doi: 10.1109/TED.2010.2087339。
[30] J. Wei et al., “Charge storage mechanism of drain induced dynamic threshold voltage shift in p-GaN gate HEMTs,” IEEE Electron Device Lett., vol. 40, no. 4, pp. 526-529, Apr. 2019, doi: 10.1109/LED.2019.2900154.
[30] J. Wei 等, “p-GaN 门 HEMT 中排水引起的动态阈值电压偏移的电荷存储机制,” IEEE 电子器件快报, 第 40 卷, 第 4 期, 第 526-529 页, 2019 年 4 月, doi: 10.1109/LED.2019.2900154.
[31] S. Pan et al., “Evaluation of trapping behaviors in forward biased Schottky-type p-GaN gate HEMTs,” IEEE Trans. Electron Devices, vol. 70, no. 7, pp. 3475-3482, Jul. 2023, doi: 10.1109/TED. 2023.3278614
[31] S. Pan 等, “正向偏置肖特基型 p-GaN 门 HEMT 的捕获行为评估,” IEEE 电子器件学报, 第 70 卷, 第 7 期, 页 3475-3482, 2023 年 7 月, doi: 10.1109/TED.2023.3278614
[32] M. Charfeddine, M. Gassoumi, H. Mosbahi, C. Gaquiére, M. A. Zaidi, and H. Maaref, “Electrical characterization of traps in AlGaN/GaN FAT-HEMT’s on silicon substrate by

C - V

and DLTS measurements,” J. Mod. Phys., vol. 2, no. 10, pp. 1229-1234, 2011, doi: 10.4236/jmp.2011.210152.
[32] M. Charfeddine, M. Gassoumi, H. Mosbahi, C. Gaquiére, M. A. Zaidi, 和 H. Maaref, “通过

C - V

和 DLTS 测量对硅基 AlGaN/GaN FAT-HEMT 中的陷阱进行电特性表征,” J. Mod. Phys., vol. 2, no. 10, pp. 1229-1234, 2011, doi: 10.4236/jmp.2011.210152.
[33] N. Sghaier et al., “Traps centers and deep defects contribution in current instabilities for AlGaN/GaN HEMT’s on silicon and sapphire substrates,” Microelectron. J., vol. 37, no. 4, pp. 363-370, Apr. 2006, doi:

10.1016 /

j.mejo.2005.05.014.
[33] N. Sghaier 等, “铝镓氮/氮化镓 HEMT 在硅和蓝宝石基底上的电流不稳定性中的陷阱中心和深缺陷贡献,” 微电子学杂志, 第 37 卷, 第 4 期, 页 363-370, 2006 年 4 月, doi:

10.1016 /

j.mejo.2005.05.014.
[34] A. Y. Polyakov and I.-H. Lee, “Deep traps in GaN-based structures as affecting the performance of GaN devices,” Mater. Sci. Eng. R, Rep., vol. 94, pp. 1-56, May 2015, doi: 10.1016/j.mser.2015.05.001.
[34] A. Y. Polyakov 和 I.-H. Lee, “GaN 基结构中的深陷阱对 GaN 器件性能的影响,” 材料科学与工程 R, 报告, 第 94 卷, 第 1-56 页, 2015 年 5 月, doi: 10.1016/j.mser.2015.05.001.
[35] W. Götz, N. M. Johnson, M. D. Bremser, and R. F. Davis, “A donorlike deep level defect in

{Al}_{0.12} {Ga}_{0.88} N

characterized by capacitance transient spectroscopies,” Appl. Phys. Lett., vol. 69, no. 16, pp. 2379-2381, Oct. 1996, doi:

10.1063 / 1.117643

.
[35] W. Götz, N. M. Johnson, M. D. Bremser, 和 R. F. Davis, “一种类似施主的深能级缺陷在

{Al}_{0.12} {Ga}_{0.88} N

中的特征通过电容瞬态光谱,” 应用物理快报, 第 69 卷, 第 16 期, 第 2379-2381 页, 1996 年 10 月, doi:

10.1063 / 1.117643

Manuscript received 16 April 2024; revised 4 June 2024; accepted 7 June 2024. Date of publication 17 June 2024; date of current version 25 July 2024. This work was supported in part by the National Natural Science Foundation of China under Grant 62174008 and in part by Beijing Municipal Education Commission under Grant KZ202110005001. The review of this article was arranged by Editor M. Meneghini. (Corresponding authors: Shiwei Feng; Xiang Zheng.)
手稿于 2024 年 4 月 16 日收到；2024 年 6 月 4 日修订；2024 年 6 月 7 日接受。出版日期为 2024 年 6 月 17 日；当前版本日期为 2024 年 7 月 25 日。本研究部分得到了中国国家自然科学基金（资助号 62174008）和北京市教育委员会（资助号 KZ202110005001）的支持。本文的审稿由编辑 M. Meneghini 安排。（通讯作者：冯士伟；郑翔。）

Zixuan Feng, Shiwei Feng, Shijie Pan, Binyu You, Boyang Zhang, Yaning Wang, and Yamin Zhang are with the College of Microelectronics, Beijing University of Technology, Beijing 100124, China (e-mail: shwfeng@bjut.edu.cn).
冯子轩、冯世伟、潘世杰、游彬宇、张博扬、王亚宁和张亚敏均来自北京工业大学微电子学院，中国北京 100124（电子邮件：shwfeng@bjut.edu.cn）。
Xuan Li was with the Institute of Semiconductor Device Reliability Physics, Beijing University of Technology, Beijing 100124, China. He is now with the Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China (e-mail: lixuan2023@ime.ac.cn).
Xuan Li 曾在中国北京 100124，北京工业大学半导体器件可靠性物理研究所工作。现在他在中国科学院微电子研究所工作，地址为中国北京 100029（电子邮件：lixuan2023@ime.ac.cn）。
Xiang Zheng is with the Center for Device Thermography and Reliability, University of Bristol, Bristol BS8 1QU, U.K. (e-mail: xiang.zheng@bristol.ac.uk).
向正在布里斯托大学设备热成像与可靠性中心工作，地址：英国布里斯托 BS8 1QU。（电子邮件：xiang.zheng@bristol.ac.uk）
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Investigation of Electrical Characteristics and Trapping Effects in p-GaN Gate HEMTs Under Electron Irradiation 在电子辐照下 p-GaN 门 HEMT 的电气特性和捕获效应的研究