多晶硅薄膜低温生长中晶粒大小的控制

以SiCl4H2为气源，用等离子体增强化学气相沉积(PECVD)方法低温快速沉积多晶硅薄膜.实验发现，在多晶硅薄膜的生长过程中，气相空间各种活性基团的相对浓度是影响晶粒大小的重要因素，随功率、H2/SiCl4流量比的减小和反应室气压的增加，晶粒增大.而各种活性基团的相对浓度依赖于PECVD工艺参数,通过工艺参数的改变，分析生长过程中空间各种活性基团相对浓度的变化，指出“气相结晶”过程是晶粒长大的一个重要因素. 关键词： 气相结晶 多晶硅薄膜 晶粒生长 SiCl4

Control of grain size during low-temperature growth of polycrystalline silicon films

Polycrystalline silicon thin films were prepared at high-speed by plasma-enhanced chemical vapor deposition technique at low temperatures using SiCl4 and H2 as source gases. It was found that the grain growth is strongly affected by the relative concentration of different active radicals in the gas-phase space. On the other hand, the relative concentration depends on the deposition conditions. With the decrease of the rf power and the H2/ SiCl4 flow ratio, and the increase in the reaction pressure, the grain size increases. By changing the deposition conditions, variations of the relative concentration were analyzed. It is suggested that the “gas-phase crystalline" is of crucial importance to the grain growth.