Journal of Semiconductors, Volume. 43, Issue 6, 062803(2022)

Optimization of recess-free AlGaN/GaN Schottky barrier diode by TiN anode and current transport mechanism analysis

Hao Wu1,2, Xuanwu Kang2, Yingkui Zheng2, Ke Wei2, Lin Zhang3, Xinyu Liu2, and Guoqi Zhang1
Author Affiliations
  • 1The Institute of Future Lighting, Academy for Engineering and Technology, Fudan University (FAET), Shanghai 200433, China
  • 2Institute of Microelectronics of the Chinese Academy of Sciences, Beijing 100029, China
  • 3Beijing Const-Intellectual Core Technology Co. Ltd, Beijing 100029, China
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    In this work, the optimization of reverse leakage current (IR) and turn-on voltage (VT) in recess-free AlGaN/GaN Schottky barrier diodes (SBDs) was achieved by substituting the Ni/Au anode with TiN anode. To explain this phenomenon, the current transport mechanism was investigated by temperature-dependent current–voltage (I–V) characteristics. For forward bias, the current is dominated by the thermionic emission (TE) mechanisms for both devices. Besides, the presence of inhomogeneity of the Schottky barrier height (b) is proved by the linear relationship between b and ideality factor. For reverse bias, the current is dominated by two different mechanisms at high temperature and low temperature, respectively. At high temperatures, the Poole–Frenkel emission (PFE) induced by nitrogen-vacancy (VN) is responsible for the high IR in Ni/Au anode. For TiN anode, the IR is dominated by the PFE from threading dislocation (TD), which can be attributed to the decrease of VN due to the suppression of N diffusion at the interface of Schottky contact. At low temperatures, the IR of both diodes is dominated by Fowler–Nordheim (FN) tunneling. However, the VN donor enhances the electric field in the barrier layer, thus causing a higher IR in Ni/Au anode than TiN anode, as confirmed by the modified FN model.

    1. Introduction

    AlGaN/GaN Schottky barrier diode (SBD) features excellent performance for high-power, high-frequency, and high-temperature applications, attributed to the outstanding properties of GaN material[1-5]. Recently, some researchers have demonstrated that AlGaN/GaN SBD has great potential for future wireless power transfer (WPT) applications[6-7]. The SBD converts the received RF signal into DC power, which determines the efficiency of the WPT system. To increase the conversion efficiency, AlGaN/GaN SBD requires a low turn-on voltage (VT) while maintaining a low reverse leakage current (IR).


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    Hao Wu, Xuanwu Kang, Yingkui Zheng, Ke Wei, Lin Zhang, Xinyu Liu, Guoqi Zhang. Optimization of recess-free AlGaN/GaN Schottky barrier diode by TiN anode and current transport mechanism analysis[J]. Journal of Semiconductors, 2022, 43(6): 062803

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    Paper Information

    Category: Articles

    Received: Dec. 9, 2021

    Accepted: --

    Published Online: Jun. 10, 2022

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