一种重掺衬底上生长硅外延层的工艺研究

Research on Process for Silicon Epitaxial Layer on Heavily Doped Substrate

随着肖特基势垒二极管对反向击穿电压一致性指标要求的进一步严格,对所需重掺衬底的硅外延层厚度和电阻率参数的均匀性指标提出了更高的要求。同时,为满足肖特基势垒二极管低正向压降的性能,对外延层过渡区宽度的控制难度加大。使用PE-2061S桶式外延炉,通过综合采取低温本征法、变流吹扫及低速外延沉积等工艺手段,成功实施了重掺衬底上窄过渡区硅外延层的生长工艺,硅外延层厚度和电阻率不均匀性均达到<1.5%的要求,而且过渡区宽度可以<1.6μm。

Schottky barrier diodes have become more stringent in their requirements for the consistency of the reverse breakdown voltage,higher requirements have been placed on the uniformity of the silicon epitaxial layer thickness and resistivity parameters of the heavily doped substrate.At the same time,in order to meet the low forward voltage drop performance of the Schottky barrier diodes,it is more difficult to control the width of the epitaxial transition region.Using the PE-2061 S barrel-type epitaxial reactor,the growth process of the silicon epitaxial layer in the narrow transition region on the heavily doped substrate is successfully implemented by comprehensively adopting the low temperature intrinsic method,variable flow purge and low speed epitaxial deposition.The non-uniformity of the thickness and resistivity of the silicon epitaxial layer meets the requirements of<1.5%,and the width of the transition region is less than 1.6μm.