用热激发电流法研究金刚石薄膜中的陷阱

Investigation on Traps in MPCVD Diamond Films by Thermal Stimulated Current Measurements

对微波等离子体化学气相沉积（ＭＰＣＶＤ）的硅衬底金刚石薄膜，做了在液氮温区注入载流子，升温测其电流－温度关系的实验．观察到ａｓ－ｇｒｏｗｎ样品有明显的热激发电流峰．重复实验时，峰基本消失．经氢等离子体在～９００℃处理２．５ｈ后，再重复实验，该峰又出现．推断热激发电流峰是由硅衬底金刚石薄膜内氢致陷阱中的载流子撤空引起的．这些能级在金刚石禁带中的陷阱是可以通过适当热处理消除的．

Carrier injection under liquid nitrogen temperature followed by thermal stimulated current(TSC) measurements were carried out for MPCVD diamond films. TSC peaks were observed obviously for as-grown samples.The peaks,however,almost disappeared after the first heating process.Having undergone hydrogen plasma treatment at～ 900 ℃ for 2.5 hours for one sample,the peaks emerge again. Thermal stimulated traps emptying is postulated to be the origin of the TSC peaks, and the traps are related to hydrogen implantation.These traps,which energy level located in the band gap of diamond, can be eliminated via proper heat treatment.