Method for fabricating self-aligned polysilicon contacts on FET source/drain areas

摘要

Improved N-channel and P-channel field effect transistor device structure having self-aligned polysilicon pads contacts and a process for making such devices has been achieved. The doped polysilicon pad contact are formed over the source/drain areas of the field effect transistors and are used to form shallow self-aligned diffused contact to the source/drain areas. These polysilicon pads provide a low resistance ohmic contacts that are free from implant damage that would otherwise cause increased junction leakage current and are free of metal spiking at the source/drain area perimeter that would cause metal contact to substrate shorts. The increased area of the polysilicon pads over the source/drain area allows for relaxed design ground rule for the contact openings, making for a more manufacturable process for Ultra Large Scale Integration applications.