Ultralow Ohmic Contact in Recess-Free Ultrathin Barrier AlGaN/GaN Heterostructures Across a Wide Temperature Range  

作　　者：Yuhao Wang Sen Huang Qimeng Jiang Xinhua Wang Jie Fan Haibo Yin Ke Wei Yingkui Zheng Xinyu Liu 

机构地区：[1]Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China [2]Institute of Microelectronics,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Journal of Electronics》2025年第1期137-145,共9页电子学报(英文版)

基　　金：supported in part by the National Key Research and Development Program of China(Grant No.2022YFB3604400);in part by the Youth Innovation Promotion Association of Chinese Academy Sciences(CAS);in part by the CAS-Croucher Funding Scheme(Grant No.CAS22801);in part by the National Natural Science Foundation of China(Grant Nos.62334012,62304252,62074161,62004213,and U20A20208);in part by the Beijing Municipal Science and Technology Commission project(Grant Nos.Z201100008420009 and Z211100007921018);in part by University of CAS;in part by the IMECAS-HKUST-Joint Laboratory of Microelectronics。

摘　　要：“Ohmic-before-passivation”process was implemented on ultrathin-barrier AlGaN(<6 nm)/GaN heterostructure to further reduce the ohmic contact resistance(R_(c)).In this process,alloyed Ti/Al/Ni/Au ohmic metal was formed first,followed by AlN/SiN_(x)passivation contributed to restore two-dimensional electron gas(2DEG)in the access region.Due to the sharp change in the concentration of 2DEG at the metal edge,a reduced transfer length consisted with lower R_(c)are achieved compared to that of ohmic contact on AlGaN(~20 nm)/GaN heterostructure with pre-ohmic recess process.Temperature-dependent current voltage measurements demonstrate that the carrier transport mechanism is dominated by thermionic field emission above 200 K and by field emission below 200 K.The“ohmic-before-passivation”process enables the relative stability of ohmic contacts between 50 K and 475 K and significantly improves the direct current characteristics of GaN-metal-insulator-semiconductor-high electron mobility transistor,offering a promising means for scaling down and enabling the utilization of low-voltage GaN-based power devices in extreme environmental conditions.

关 键 词：AlGaN/GaN heterostructure Recess-free Ultrathin barrier Ohmic contact Transfer length Cryogenic temperature 

分 类 号：TN386[电子电信—物理电子学]