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Title: Investigation of abrupt degradation of drain current caused by under-gate crack in AlGaN/GaN high electron mobility transistors during high temperature operation stress

In this paper, we investigate the degradation mode and mechanism of AlGaN/GaN based high electron mobility transistors (HEMTs) during high temperature operation (HTO) stress. It demonstrates that there was abrupt degradation mode of drain current during HTO stress. The abrupt degradation is ascribed to the formation of crack under the gate which was the result of the brittle fracture of epilayer based on failure analysis. The origin of the mechanical damage under the gate is further investigated and discussed based on top-down scanning electron microscope, cross section transmission electron microscope and energy dispersive x-ray spectroscopy analysis, and stress simulation. Based on the coupled analysis of the failure physical feature and stress simulation considering the coefficient of thermal expansion (CTE) mismatch in different materials in gate metals/semiconductor system, the mechanical damage under the gate is related to mechanical stress induced by CTE mismatch in Au/Ti/Mo/GaN system and stress concentration caused by the localized structural damage at the drain side of the gate edge. These results indicate that mechanical stress induced by CTE mismatch of materials inside the device plays great important role on the reliability of AlGaN/GaN HEMTs during HTO stress.
Authors:
; ; ; ; ; ; ; ; ; ;  [1]
  1. Science and Technology on Reliability Physics and Application of Electronic Component Laboratory, The 5th Electronics Research Institute of the Ministry of Industry and Information Technology, 510610 Guangzhou (China)
Publication Date:
OSTI Identifier:
22492738
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CRACKS; CROSS SECTIONS; DAMAGE; ELECTRON MOBILITY; FRACTURES; GALLIUM NITRIDES; METALS; OPERATION; RELIABILITY; SCANNING ELECTRON MICROSCOPY; SEMICONDUCTOR MATERIALS; SIMULATION; STRESSES; THERMAL EXPANSION; TRANSISTORS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY SPECTROSCOPY