两种不同结构n型GaN基肖特基二极管电学特性

I-V Characteristics of Two Au/Ni/n-GaN Schottky Diodes with Different Structure

实验研究了两种由ICP刻蚀不同结构的n型GaN材料与金属接触形成的肖特基二极管的I-V特性,分析计算了GaN基肖特基二极管的势垒高度和理想因子。研究发现n型GaN半导体材料表面费米能级钉扎,且费米能级的钉扎对n型GaN材料表面的金半接触所形成的肖特基势垒高度起决定性作用;结果表明表面经过ICP刻蚀后,n型GaN表面的氧化层消除,价带中态密度增多,有利于载流子的遂道效应与金属较易形成欧姆接触。

The rectifying characteristics of two Schottky diodes with different structures were investigated. These two different structures were processed by induced couple plasma （ICP） etching,of which I-V characteristic curve, reverse leakage current density, the Schottky barrier height, and the ideality factor were measured and extracted. It is found that the Schottky barrier height is determined by pinned Fermi level of the n-GaN films. As the oxide was removed due to the ICP etching processing, the surface states density was increased, thus the chance of tunneling. Therefore the contact between metal and n-GaN of the transition is more Ohmic-like after ICP etching.