氟基等离子体处理对高Al组分AlGaN肖特基接触反向漏电的改善

Improvement on Leakage Current for High Al-content AlGaN Schottky Diode by Fluoride-based Plasma Treatment

在沉积肖特基金属之前,对非掺的Al0.45Ga0.55N采用了不同时间的氟基等离子体处理,其中Al组分对应日盲波段。与未做氟基等离子体处理的样品相比,经过处理的Al0.45Ga0.55N肖特基二极管在反向-10V的漏电流密度随处理时间的增加而减少,其中处理1min的样品的漏电流密度减少了5个数量级。X射线光电子谱分析证明了处理过的样品表面Ga-F和Al-F键的形成。反向漏电的减少可能是由氟基等离子体处理耗尽了电子和有效钝化了表面态导致的。

Fluoride-based plasma treatment was used prior to the Schottky evaporation on the undoped Al0.45Ga0.55N,in which the Al content corresponded to the solar-blind wavelength.Compared with the sample without F-treatment,the reverse leakage current density at-10 V of Al0.45Ga0.55N Schottky diodes decreased with increasing treatment time.The leakage current density of the sample with F-treatment for 1 min was reduced by 5 orders of magnitude.The formation of Ga-F bond and Al-F bond after treatment was confirmed by X-ray photoemission spectroscopy（XPS）.The reduction of leakage current was attributed to the depletion of electron and the passivation of surface states by fluoride-based plasma treatment.