Method for novel SOI DRAM BICMOS NPN

摘要

There is disclosed herein a unique fabrication sequence and the structure of a vertical silicon on insulator (SOI) bipolar transistor integrated into a typical DRAM trench process sequence. A DRAM array utilizing an NFET allows for an integrated bipolar NPN sequence. Similarly, a vertical bipolar PNP device is implemented by changing the array transistor to a PFET. Particularly, a BICMOS device is fabricated in SOI. The bipolar emitter contacts and CMOS diffusion contacts are formed simultaneously of polysilicon plugs. The CMOS diffusion contact is the plug contact from bitline to storage node of a memory cell.