衬底温度对低温制备纳米晶硅薄膜的影响

Effect of substrate temperature on the nano-crystalline silicon thin film deposited at low temperature

采用传统的射频等离子体增强化学气相沉积技术,在较高的工作气压130Pa和较高的射频功率70W下,在>100℃的低温下,以0.14nm/s速率制备出优质的纳米晶硅薄膜。研究结果表明,薄膜晶化率和沉积速率与衬底温度有密切关系。当衬底温度>100℃,薄膜由非晶相向晶相转化,随着衬底温度的进一步升高,薄膜晶化率增大,当温度为300℃时,薄膜的晶化率达82%,暗电导率为10-4Ω-1.cm-1数量级,激活能为0.31eV。当薄膜晶化后,沉积速率随衬底温度升高而略有增加。

Nano-crystalline silicon thin films（nc-Si： H） with deposition rate of 0. 14nm/s were prepared by the conventional plasma enhanced chemical vapor deposition（PECVD） technique under the higher deposition pressure（130Pa）,higher RF-power（70W） and low substrate temperature over 100℃. The results showed that the crystalline fraction and deposition rate are in close relation with the substrate temperature. When the substrate temperature changed from 100-150℃, the films change from amorphous phase to crystalline phase. Then the crystalline fraction increases with the increase in substrate temperature. When the substrate temperature is 300℃, the crystalline fraction reaches 82 %, dark-conductivity value is about 10^-4Ω^-1·cm^-1, activation energies is 0.31eV. The deposition rate increases slightly with the increasing of substrate temperature when the films are crystallized.