AlN Surface Passivation of GaN-Based High Electron Mobility Transistors by Plasma-Enhanced Atomic Layer Deposition

• Published in: Nanoscale research letters Vol. 12; no. 1; p. 315
• Main Authors: Tzou, An-Jye, Chu, Kuo-Hsiung, Lin, I-Feng, Østreng, Erik, Fang, Yung-Sheng, Wu, Xiao-Peng, Wu, Bo-Wei, Shen, Chang-Hong, Shieh, Jia-Ming, Yeh, Wen-Kuan, Chang, Chun-Yen, Kuo, Hao-Chung
• Format: Journal Article
• Language: English
• Published: New York Springer US 27-04-2017; Springer Nature B.V; SpringerOpen
• Subjects: 3rd International Conference on ALD Applications & 2016 China ALD conference; Aluminum nitride; Atomic layer deposition (ALD); Atomic layer epitaxy; Chemistry and Materials Science; Collapse; Current collapse; Deposition; Gallium; Gallium nitrides; GaN; High electron mobility transistor (HEMT); High electron mobility transistors; High temperature; Hydrogen plasma; Materials Science; Mobility; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Passivity; Photoelectron spectroscopy; Plasma; Plasmas (physics); Pretreatment; Refractivity; Semiconductor devices; Spectroscopy; Spectrum analysis; Surface passivation; Temperature measurement; Thermal stability; Threshold voltage; Voltage; X ray photoelectron spectroscopy; Current collapse; High electron mobility transistor (HEMT); GaN; Surface passivation; Atomic layer deposition (ALD)
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-017-2082-0

We report a low current collapse GaN-based high electron mobility transistor (HEMT) with an excellent thermal stability at 150 °C. The AlN was grown by N
2
-based plasma enhanced atomic layer deposition (PEALD) and shown a refractive index of 1.94 at 633 nm of wavelength. Prior to deposit AlN on III-nitrides, the H
2
/NH
3
plasma pre-treatment led to remove the native gallium oxide. The X-ray photoelectron spectroscopy (XPS) spectroscopy confirmed that the native oxide can be effectively decomposed by hydrogen plasma. Following the in situ ALD-AlN passivation, the surface traps can be eliminated and corresponding to a 22.1% of current collapse with quiescent drain bias (
V
DSQ
) at 40 V. Furthermore, the high temperature measurement exhibited a shift-free threshold voltage (
V
th
), corresponding to a 40.2% of current collapse at 150 °C. The thermal stable HEMT enabled a breakdown voltage (BV) to 687 V at high temperature, promising a good thermal reliability under high power operation.