面向高性能器件的SIPOS薄膜制备:沉积压力的优化与影响分析OA

To enhance the within-wafer uniformity of semi-insulating polysilicon(SIPOS)films and the withstand voltage performance of devices,the synergistic effect of pressure and the N2O/SiH4 gas flow ratio(γ)in the low-pressure chemical vapor deposition process is systematically investigated.A series of SIPOS films are prepared by fixing the process temperature and adjusting the γ value and deposition pressure.The results indicate that film uniformity is insensitive to pressure variations at low γ values.However,under highγ conditions,low deposition pressure leads to significant radial and axial concentration gradients of reaction gases on the wafer surface.These gradients persist due to limited surface diffusion,resulting in within-wafer non-uniformity in both film thickness and oxygen content.This non-uniformity ultimately degrades the device's withstand voltage performance and reliability.Consequently,a moderate deposition pressure is identified as the optimal process window to balance excellent film uniformity with high withstand voltage characteristics.