Effect of heat treatment on Ni/Au Ohmic contacts to p-type GaN

Li Chien Chen, Jin Kuo Ho, Fu Rong Chen, Ji Jung Kai, Li Chang, Chang Shyang Jong, Chien C. Chiu, Chao Nien Huang, Kwang Kuo Shih

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21 Scopus citations


The effect of heat treatment temperature on the microstructure and specific contact resistance of oxidized Ni(5 nm)/Au(5 nm) contacts to p-type GaN was investigated. The minimum specific contact resistance (ρc) obtained was 4×10-6 Ω cm2 after heat treating at 500 °C in air for 10 min. The cross-sectional microstructure of heat treated Ni/Au films on p-type GaN was examined with transmission electron microscope (TEM) in conjunction with compositional analyses. The high value of ρc for samples heat treated at lower temperatures (<400 °C) was attributed to the fact that Au islands and crystalline NiO detached from the p-type GaN. When the temperature increased to 500 °C, NiO films and Au islands epitaxially constructed on p-type GaN matrix. The crystalline NiO may play a crucial role in the formation of low-resistance ohmic contact to p-GaN. Increasing the temperature further to 600 °C, large voids adjacent to p-GaN were observed which resulted in the reduction of contacting area deteriorating the contact resistance.

Original languageEnglish
Pages (from-to)773-777
Number of pages5
JournalPhysica Status Solidi (A) Applied Research
Issue number1
StatePublished - 1 Nov 1999
EventProceedings of the 1999 3rd International Conference on Nitride Semiconductors (ICNS'99) - Montpellier, France
Duration: 4 Jul 19999 Jul 1999

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