標題: Microstructural investigation of oxidized Ni/Au ohmic contact to p-type GaN
作者: Chen, LC
Chen, FR
Kai, JJ
Chang, L
Ho, JK
Jong, CS
Chiu, CC
Huang, CN
Chen, CY
Shih, KK
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 1999
摘要: The microstructure of oxidized Ni/Au films on p-GaN was examined to elucidate the formation of a low resistance ohmic contact to p-GaN with a field-emission gun transmission electron microscope in conjunction with composition analyses. The p-GaN/Ni/Au samples were heat treated at 500 degrees C in air mainly composed of a mixture of crystalline NiO, Au, and amorphous Ni-Ga-O phases. Small voids adjacent to the p-GaN film were also observed. The as-deposited Au film converted into discontinuous islands containing small amounts of Ni that connect with p-GaN. NiO formed a continuous film at the surface that covers the Au islands and the amorphous Ni-Ga-O phases. Moreover, NiO partially contacts p-GaN as well as Au islands and the amorphous Ni-Ga-O phase. The orientation relationship of the crystalline NiO, Au-rich islands, and p-GaN film was identified as NiO(111)//Au(11 (1) over bar)//GaN(0002) and NiO[1 (1) over bar 0]//Au[1 (1) over bar 0]//GaN[11 (2) over bar 0]. The results suggested that Ni atoms diffuse through the Au layer onto the surface and react with oxygen to form NiO, whereas Au atoms diffuse towards the inside to form a Au-Ni alloy. The microstructural examination indicated that the crystalline NiO and/or the amorphous Ni-Ga-O phases may significantly affect the low resistance ohmic contact to p-GaN. (C) 1999 American Institute of Physics. [S0021-8979(99)05219-6].
URI: http://hdl.handle.net/11536/31043
ISSN: 0021-8979
期刊: JOURNAL OF APPLIED PHYSICS
Volume: 86
Issue: 7
起始頁: 3826
結束頁: 3832
顯示於類別:期刊論文


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