温度对高速微晶硅薄膜沉积速率及其特性的影响

Influence of Temperature on Deposition Rate and Properties of Microcrystalline Silicon Flims

采用超高频(VHF)结合高压(HP)的技术路线,在较高SiH4浓度(SC)下实现了微晶硅(μc-Si:H)薄膜的高速沉积,考察了衬底温度在化学气相沉积(CVD)过程中对薄膜的生长速率以及光电特性的影响。结果表明:薄膜微结构特性随衬底温度变化是导致薄膜电学特性随衬底温度变化的根本原因;HP与低压条件下沉积的μc-Si:H薄膜的特性随温度变化的规律不同,在试验温度范围内,HP高速沉积的μc-Si:H薄膜生长速率不同于低压时随温度升高而下降的趋势,而是先增大后趋于平稳,晶化率随温度升高也不是单调增加,而是先增加后减小。

The deposition of （μc-Si：H） films with a high rate is investigated using very-high-frequency plasma-enhanced chemical vapor（VHF-PECVD） under high pressure. Device-grade μc-Si：H films at high deposition rate are obtained with high density silane. And the influences of substrate＇s temperature on the deposition rate and the properties of microcrystalline silicon films during the CVD process are studied. By detailed analysis,the changed microstructure of microcrystalline silicon due to the variation of the substrate temperature actually resultes in the change of the microcrystalline silicon electrnic characteristics. Furthermore,the experimental results also demonstrate that the changing trends of the microcrystalline silicon properties with the substrate temperature are different between high pressure and low pressure. It is known that the deposition rates of the microcrystalline silicon films decrease with the temperature, and the crystalline volume fractions increase with the temperature under low pressure. However,the deposition rates of the microcrystalline silicon films increase firstly and then keep constant beyond a critical temperature point, and the crystalline volume fractions firstly increase and then decrease with temperature under high pressure.