펄스 SiH₄플라즈마 화학기상증착 공정에서 입자 성장에 대한 펄스 변조의 영향

Effects of Pulse Modulations on Particle Growth in Pulsed SiH₄ Plasma Chemical Vapor Deposition Process

We analyzed systematically particle growth in the pulsed SiH_4 plasmas by a numerical method and investigated the effects of pulse modulations (pulse frequencics, duty ratios) on the particle growth. We considered effects of particle charging on the particle growth by coagulation during plasma-on. During plasma-on (t_(on)), the particle size distribution in plasma reactor becomes bimodal (small sized and large sized particles groups). During plasma-off (t_(off)), there is a single mode of large sized particles which is widely dispersed in the particle size distribution. During plasma on, the large sized particles grows more quickly by fast coagulation between small and large sized particles than during plasma-off. As the pulse frequency decreases, or as the duty ratio increases, t_(on) increases and the large sized particles grow taster. On the basis of these results, the pulsed plasma process can be a good method to suppress efficiently the generation and growth of particles in SiH_(4) PCVD process. This systematical analysis can be applied to design a pulsed plasma process for the preparation of high quality thin films.