硼掺杂纳米硅薄膜的热退火效应研究

The Effects of Thermal Annealing on the Characteristics of Boron Doped Nanocrystalline Silicon

采用等离子体增强化学气相沉积技术制备了硼掺杂氢化非晶硅薄膜,然后经过不同温度的热退火处理,获得硼掺杂纳米硅薄膜.结果表明,退火温度为700℃时,样品中开始有纳米晶形成,随着退火温度的增加,在1 000℃时,薄膜的晶化率达到77%,晶粒大小为3.9 nm.退火温度低于600℃时,光学带隙随着退火温度的升高而变窄,高于600℃时,带隙随着退火温度的升高而展宽,对此讨论了缺陷态和晶化度对样品光学带隙的影响.

Boron-doped hydrogenated amorphous silicon films were prepared by using plasma enhanced chemical vapor deposition system. As-deposited films were annealed at various temperatures in order to obtain the nanocrystalline silicon films with boron doping. It can be found that the nanocrystalline silicon can be formed at the annealing temperature of 700℃. At annealing temperature of 1000 ℃, the crystallinity reaches to 77.0% and the grain size is about 3.9 nm. It was found that the optical band gap decreases with increasing annealing temperature below 600 ℃, while it becomes wide when the sample is annealed above 600 ℃. The effect of defect states and the crystallinity on the optical band gap was discussed for samples.