J. Semicond. > 2015, Volume 36 > Issue 7 > 074005
|

SEMICONDUCTOR DEVICES

Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress

Lei Shi, Shiwei Feng, Kun Liu and Yamin Zhang

+ Author Affiliations
DOI: 10.1088/1674-4926/36/7/074005

PDF

Abstract: The phenomenon of self-changing on the device parameters and characteristics after a step voltage stress was applied to the gate is studied in AlGaN/GaN high electron mobility transistors. The device was measured every 5 min after the stress was removed. The large-signal parasitic source (drain) resistance, transfer characteristics, threshold voltage, drain-source current, gate-source (drain) reverse current-voltage characteristics changed spontaneously after the removal of the stress. The time constant of the self-changing was about 25-27 min. The gate-source (drain) capacitance-voltage characteristics were constant during this process. Electrons were trapped by the surface states and traps in the AlGaN barrier layer when the device was under stress. The traps in the AlGaN barrier layer then released electrons in less than 10 s. The surface states released electrons continuously during the entire measurement stage, leading to the self-changing of mearsurement result.

Key words: AlGaN/GaN HEMTs, surface states, self-changing, stress



[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
Fig. 1.  Cross section of device structure.

DownLoad: Full-Size Img PowerPoint
Fig. 2.  The changes of the normalized $R_{\rm S}$ and $R_{\rm D}$ with time (time $=$ 0-120 min, step $=$ 5 min). The data were fitted with exponential function: $y = y_0 + A_1 \exp(-(x-x_0)/t_1), $ where $y$ represents $R_{\rm S}$ and $R_{\rm D}$, and $x$ represents time. The time constants $(t_1)$ for curves $C$ and $D$ were 25.2 min and 25.6 min, respectively.

DownLoad: Full-Size Img PowerPoint
Fig. 3.  Transfer characteristics at time $=$ 0, 10, 20, 30, 60, 120 min. ($V_{\rm DS}$ $=$ 5 V, $V_{\rm GS}$ $=$ $-2$ to $-0.5$ V, step $=$ 0.005 V). The inset shows $V_{\rm GS (th)}$ ($V_{\rm GS}$ at $I_{\rm DS}$ $=$ 1 mA/mm) and normalized $I_{\rm Dmax}$ ($V_{\rm DS}$ $=$ 5 V, $V_{\rm GS}$ $=$ 0 V) (time $=$ 0-120 min, step is 5 min). The curves were fitted with the exponential equation: $y = y_0 + A_1 \exp(-(x-x_0)/t_1), $ where $y$ represents $V_{\rm GS(th)}$, $I_{\rm Dmax}$ and $x$ represents time. The time constants, $t_1$ for curves $G$ and $H$ were 27.7 min and 27.2 min, respectively.

DownLoad: Full-Size Img PowerPoint
Fig. 4.  Band diagram of the AlGaN/GaN heterostructure showing the effect of electrons trapped by surface states. (a) Time $=$ 0 min. (b) Time $=$ 120 min.

DownLoad: Full-Size Img PowerPoint
Fig. 5.  Reverse $I$-$V$ characteristics between the gate and source at time $=$ 0, 10, 20, 30, 60, 120 min. ($V_{\rm GS}$ $=$ $-5$ to 0 V, step $=$ 0.05~V). The inset shows the $I_{\rm GS}$-time curves at $V_{\rm GS}$ $=$ $-5$ V and $-4.5$~V (time $=$ 0-120 min, step is 5 min). The curves were fitted with the exponential equation: $y = y_0 + A_1 \exp(-(x-x_0)/t_1), $ where $y$ represents $I_{\rm GS}$ and $x$ represents time. The time constants, $t_1$ for curves $K$ and $L$ were 25.7 min and 26.5 min, respectively.

DownLoad: Full-Size Img PowerPoint
Fig. 6.  Schematic diagram of the gate-source capacitance and the gate-drain capacitance in the sample.

DownLoad: Full-Size Img PowerPoint
Fig. 7.  $C$-$V$ characteristics between the gate and source at time $=$ 0, 10, 20, 30, 60, 120 min. ($V_{\rm GS}$ $=$ $-5$ V, step $=$ 0.05 V). The inset shows the $C_{\rm gs}$-time curves at $V_{\rm GS}$ $=$ $-5$ V and $-4.5$ V (time $=$ 0-120~min, step $=$ 5 min). The curves were linear and were fitted with the equation: $y = a + bx, $ where $y$ represents $C_{\rm gs}$ and $x$ represents time. The slopes ($b$) of lines $O$ and $P$ were $-1.22$ $\times$ 10$^{-5}$ and $-1.40$ $\times$ 10$^{-5}$, respectively.

DownLoad: Full-Size Img PowerPoint
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]

    • Search

    Advanced Search >>

    GET CITATION

    shu

    Export: BibTex EndNote

    Article Metrics

    Article views: 2292 Times PDF downloads: 21 Times Cited by: 0 Times

    History

    Received: 05 September 2014 Revised: Online: Published: 01 July 2015

    Catalog

      Email This Article

      User name:
      Email:*请输入正确邮箱
      Code:*验证码错误
      Send
      Article Navigation >  Journal of Semiconductors  > 2015  >  36(7): 074005
      Lei Shi, Shiwei Feng, Kun Liu, Yamin Zhang. Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress[J]. Journal of Semiconductors, 2015, 36(7): 074005. doi: 10.1088/1674-4926/36/7/074005 ****L Shi, S W Feng, K Liu, Y M Zhang. Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress[J]. J. Semicond., 2015, 36(7): 074005. doi: 10.1088/1674-4926/36/7/074005.
      Citation:
      Lei Shi, Shiwei Feng, Kun Liu, Yamin Zhang. Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress[J]. Journal of Semiconductors, 2015, 36(7): 074005. doi: 10.1088/1674-4926/36/7/074005 ****
      L Shi, S W Feng, K Liu, Y M Zhang. Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress[J]. J. Semicond., 2015, 36(7): 074005. doi: 10.1088/1674-4926/36/7/074005.
      shu

      Mechanism of the self-changing parameters and characteristics in AlGaN/GaN high-electron mobility transistors after a step voltage stress

      DOI: 10.1088/1674-4926/36/7/074005

      • College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China

      Funds:

      Project supported by the National Natural Science Foundation of China (Nos. 61376077, 61201046, 61204081), and the Beijing Natural Science Foundation (Nos. 4132022, 4122005).

      • Received Date: 2014-09-05
      • Accepted Date: 2015-02-13
      • Published Date: 2015-01-25

      Catalog

        Journal of Semiconductors © 2017 All Rights Reserved   京ICP备05085259号-2

        /

        DownLoad:  Full-Size Img  PowerPoint
        Return
        Return