F element existed in HF substitutes easily the -OH to form stable Si-F, and it also breaks easily the Si~0 bond to create more Si-OH, which creates SiF_4 gas in the end. The origin of the trap states is the dangling bond lied on the wall of hole.

• HF当中存在活泼的F元素,它容易取代-OH,形成稳定的Si-F,也容易打断Si-O键,制造出额外的Si-OH,最后形成SiF_4以气体的形式释放出去。