论文部分内容阅读
在p-GaN上蒸发Ni/Au电极前,采用王水、HCl、缓冲HF进行前表面处理,O2气氛下退火后,比较各电极样品的I-V特性和表面形貌。结果显示无表面处理时接触电阻最小,且溶剂处理后残留的电解质会影响电极的电流特性和稳定性。用俄歇电子能谱(AES)测试不同元素随深度分布情况,发现高温退火过程中NiO的形成有自动清洁p-GaN表面的作用,因此对于Ni基电极前表面处理不是必需的。再将样品用10%草酸溶液处理,其I-V特性显示接触电阻率明显下降;X射线光电子能谱(XPS)测试显示草酸溶液处理后电极表面Ni含量显著减少,而Au元素信号峰增强,说明表面高阻p型NiO被有效除去,对改善接触性能具有实际意义。
Before evaporating the Ni / Au electrode on p-GaN, I-V characteristics and surface topography of each electrode sample were compared after pre-treatment with aqua regia, HCl, buffered HF and annealing in O2 atmosphere. The results show that the contact resistance is minimal without surface treatment, and the residual electrolyte after solvent treatment can affect the current characteristics and stability of the electrode. The distribution of different elements along the depth was tested by Auger electron spectroscopy (AES). It was found that the formation of NiO during high temperature annealing has the effect of automatically cleaning the surface of p-GaN and therefore is not necessary for Ni-based electrode front surface treatment. The IV characteristics show that the contact resistivity decreased obviously after X-ray photoelectron spectroscopy (XPS) test showed that the content of Ni on the surface of the electrode decreased significantly after the treatment with oxalic acid solution, while the signal peak of the Au element increased, indicating that the surface High-resistance p-type NiO is effectively removed, to improve the contact performance of practical significance.