Journal Article

Improving Transport Properties of GaN-Based HEMT on Si (111) by Controlling SiH4 Flow Rate of the SiNx Nano-Mask

Huynh, Sa-Hoang, Xuan, Rong, Wu, Ssu-Kuan, Mai, Thi Thu, Wen, Hua-Chiang, Jiang, Jhen-Gang, Chou, Wu-Ching, Yen, Sui-An, Liu, Cheng-Wei, Dai, Jin-Ji, Hu, Chih-Wei

2021

Overview

The AlGaN/AlN/GaN high electron mobility transistor structures were grown on a Si (111) substrate by metalorganic chemical vapor deposition in combination with the insertion of a SiNx nano-mask into the low-temperature GaN buffer layer. Herein, the impact of SiH4 flow rate on two-dimensional electron gas (2DEG) properties was comprehensively investigated, where an increase in SiH4 flow rate resulted in a decrease in edge-type threading dislocation density during coalescence process and an improvement of 2DEG electronic properties. The study also reveals that controlling the SiH4 flow rate of the SiNx nano-mask grown at low temperatures in a short time is an effective strategy to overcome the surface desorption issue that causes surface roughness degradation. The highest electron mobility of 1970 cm2/V·s and sheet carrier concentration of 6.42 × 1012 cm−2 can be achieved via an optimized SiH4 flow rate of 50 sccm.

• Publisher: MDPI AG
• Subject: Aluminum gallium nitrides / Buffer layers / Carrier density / Coalescing / Dislocation density / Electron gas / Electrons / Etching / Flow velocity / Gallium nitrides / Grain size / High electron mobility transistors / Low temperature / Metalorganic chemical vapor deposition / Morphology / Scanning electron microscopy / Semiconductor devices / Silicon substrates / Surface roughness / Threading dislocations / Transport properties / Two dimensional flow