Physical analysis of normally-off ALD Al_(2)O_(3)/GaN MOSFET with different substrates using self-terminating thermal oxidation-assisted wet etching technique  

作　　者：Cheng-Yu Huang Jin-Yan Wang Bin Zhang Zhen Fu Fang Liu Mao-Jun Wang Meng-Jun Li Xin Wang Chen Wang Jia-Yin He Yan-Dong He 黄成玉;王金延;张斌;付振;刘芳;王茂俊;李梦军;王鑫;汪晨;何佳音;何燕冬(School of Integrated Circuits,Peking University,Beijing 100871,China;Beijing Chip Identification Technology Co.,Ltd,Beijing 102200,China)

机构地区：[1]School of Integrated Circuits,Peking University,Beijing 100871,China [2]Beijing Chip Identification Technology Co.,Ltd,Beijing 102200,China

出　　处：《Chinese Physics B》2022年第9期511-518,共8页中国物理B（英文版）

基　　金：Project supported by the Research on Key Techniques in Reliability of Low Power Sensor Chip for IOTIPS and the Technology Project of Headquarters,State Grid Corporation of China(Grant No.5700-202041397A-0-0-00).

摘　　要：Based on the self-terminating thermal oxidation-assisted wet etching technique,two kinds of enhancement mode Al_(2)O_(3)/GaN MOSFETs(metal-oxide-semiconductor field-effect transistors)separately with sapphire substrate and Si sub-strate are prepared.It is found that the performance of sapphire substrate device is better than that of silicon substrate.Comparing these two devices,the maximum drain current of sapphire substrate device(401 mA/mm)is 1.76 times that of silicon substrate device(228 mA/mm),and the field-effect mobility(μ_(FEmax))of sapphire substrate device(176 cm^(2)/V·s)is 1.83 times that of silicon substrate device(96 cm^(2)/V·s).The conductive resistance of silicon substrate device is 21.2Ω-mm,while that of sapphire substrate device is only 15.2Ω·mm,which is 61%that of silicon substrate device.The significant difference in performance between sapphire substrate and Si substrate is related to the differences in interface and border trap near Al_(2)O_(3)/GaN interface.Experimental studies show that(i)interface/border trap density in the sapphire substrate device is one order of magnitude lower than in the Si substrate device,(ii)Both the border traps in Al_(2)O_(3) dielectric near Al_(2)O_(3)/GaN and the interface traps in Al_(2)O_(3)/GaN interface have a significantly effect on device channel mobility,and(iii)the properties of gallium nitride materials on different substrates are different due to wet etching.The research results in this work provide a reference for further optimizing the performances of silicon substrate devices.

关 键 词：atomic layer deposition Al_(2)O_(3)/GaN MOSFET NORMALLY-OFF interface/border traps thermal oxidation-assisted wet etching 

分 类 号：TN386[电子电信—物理电子学]