A REVIEW OF Si EPITAXY: 40 YEARS OF PROGRESS WITH AN EXTRAORDINARY FUTURE

摘要

The epitaxial deposition of Si, initially embraced for discrete bipolar devices, has become widely accepted for bipolar, BiCMOS and CMOS ICs. Heteroepitaxial SiGe HBT technology has resulted in a rapid acceptance of SiGe HBT devices in BiCMOS communications ICs. The selective epitaxial growth of SiGe has found application in sub-lOOnrn CMOS logic devices for improving the PMOS device Ion/IOff ratio. CVD Si epitaxy initially embraced SiCU in H2 at a deposition temperature of -1200C. Today, deposition temperatures from <500C to >1200C can be accommodated by choosing from a variety of precursors (Si3H8, Si2H6, SiRt, Sil^Ck, SLHCI3 & SiCU). Initially, all production Si epi processes were performed at atmospheric pressure. The used of reduced pressure is now common and provides benefits for dopant profile abruptness, selective epi loading effects and poly/epi growth rate ratio. Epitaxial deposition equipment has evolved from inductively heated batch reactors to radiantly heated single wafer process tools. The load locks on present day single wafer tools have enabled high quality epi processing at very low temperatures.