NiO removal of Ni/Au Ohmic contact to p-GaN after annealing

• Published in: Journal of semiconductors Vol. 30; no. 2; pp. 101 - 104
• Main Author: 林孟喆 曹青 颜廷静 张书明 陈良惠
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2009
• Subjects: NiO; 半导体技术; 接触电阻; 气敏电气阻
• ISSN: 1674-4926
• DOI: 10.1088/1674-4926/30/2/026001

The Ni/Au contact was treated with oxalic acid after annealing in 02 ambient, and its 1-V characteristic showed the property of contact has been obviously improved. An Auger electron spectroscopy （AES） depth profile of the contact as-annealed showed that the top layer was highly resistive NiO, while an X-ray photo-electron spectroscopy （XPS） of oxalic acid treated samples indicated that the NiO has been removed effectively. A scanning electron microscope （SEM） was used to observe the surface morphology of the contacts, and it was found that the lacunaris surface right after annealing became quite smooth with lots of small Au exposed areas after oxalic acid treatment. When the test probe or the subsequently deposited Ti/Au was directly in contact with these small Au areas, they worked as low resistive current paths and thus decrease the specific contact resistance.