分步法高速沉积微晶硅薄膜

为提高微晶硅薄膜的纵向结晶性能, 在甚高频等离子体增强化学气相沉积技术的基础上, 采用过渡参数缓变和两步法相结合的方法在普通玻璃衬底上高速沉积薄膜. 当功率密度为2.1 W/cm², 硅烷浓度在6%和9.6%之间变化时, 从薄膜方向和玻璃方向测算的Raman晶化率的差异维持在2%以内. 硅烷浓度为9.6%时, 薄膜沉积速率可达3.43 nm/s, 从薄膜方向和玻璃方向测算的Raman晶化率分别为50%和48%, 差异的相对值仅为4.0%. 合理控制过渡阶段的参数变化, 可使两个方向的Raman晶化率差值下降到一个百分点. 表明采用新方法制备薄膜, 不仅可以抑制非晶孵化层的形成, 改善微晶硅薄膜的纵向结构, 还为制备优质薄膜提供了较宽的参数变化空间. 关键词： 微晶硅薄膜 非晶孵化层 高速沉积 甚高频等离子体增强化学气相沉积

High-rate deposition of microcrystalline silicon thin film by multi-step method

To improve the uniformity of crystalline volume fraction (X_c) along the deposition direction in microcrystalline silicon films, very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD), combined with parameters smoothly changed two-step method, is adopted to prepare high-rate microcrystalline silicon films on glass subtrates. With a power density of 2.1 W/cm², silane concentration between 6% and 9.6%, a difference between X_c measured in the film direction and that in the glass direction, is just 2 percent. With a silane concentration of 9.6%, X_c, measured in the film direction and the glass direction respectively reach 50% and 48%, close to 2 percent, relative difference just 4 percent, whereas the deposition rate reaches 3.43 nm/s. What is more, X_c difference can reduce to 1 percent by strictly controlling the transitional parameters. It shows that the new deposition method not only curb the incubation layers and improve the vertical structure, but also give a larger range for film optimizing in the future.