Ge ion implantation for heterostructure formation in Si/Ge/sub x/Si/sub 1-x/ heterojunction bipolar transistors

Si/Ge/sub x/Si/sub 1-x/ heterojunction n-p-n bipolar transistors (HBT) with a double polysilicon self-aligned structure were fabricated by using high dose Ge implantation for the formation of the Si/Ge/sub x/Si/sub 1-x/ heterostructure and BF/sub 2/ implantation for base doping. The Si/Ge/sub x/Si/sub 1-x/ heterostructure fabrication profess is studied in terms of potential wafer throughput. HBT electrical performances are investigated and compared to reference pure Si transistors.