LPCVD多晶硅形貌对氧化层击穿特性的影响

Effects of Morphology on Oxide Breakdown Characteristics of Polysilicon Grown by LPCVD

摘要:

多晶硅表面对于电荷耦合器件(CCD)的制作非常重要。采用扫描电子显微镜(SEM)和电学分析技术研究了低压化学气相(LPCVD)法淀积的多晶硅形貌对击穿特性的影响。研究结果表明,减小多晶硅表面颗粒尺寸有助于改善多晶硅氧化层击穿特性。多晶硅氧化层击穿特性与多晶硅和绝缘层交界面的平滑度有关。多晶硅薄膜表面平整度变差,则多晶硅与氧化层之间的界面平滑性变差,多晶硅介质层击穿强度降低。

Abstract:

The surface morphology of the polysilicon is very important for the fabrication of charge-coupled devices (CCD). In this paper, the effects of morphology on its oxide breakdown characteristics of polysilicon grown by low-pressure chemical vapor deposition (LPCVD) were studied by means of scanning electron microscopy (SEM) and electrical measurement. It is found that the breakdown characteristic can be improved by decreasing the particle size on the polysilicon layer, and it is related to the interface smoothness between the polysilicon and insulating layer. As the surface of polysilicon becomes rougher, the interface smoothness between the polysilicon and its oxide becomes worse, and then the breakdown strength of polysilicon oxide decreases.