HYDROGEN IMPLANT FOR BUFFER ZONE OF PUNCH-THROUGH NON EPI IGBT

摘要

An IGBT is formed in a thin (less than 250 microns thick) float zone silicon wafer using a hydrogen implant to form an N<+> buffer layer at the bottom of the wafer. A weak anode is formed on the bottom of the wafer. A single hydrogen implant, or a plurality of hydrogen implants of progressively shallower depth and increasing dose can be used to form the implant in a diffused float zone wafer. The process may also be used to form an N<+> contact region in silicon to permit a good ohmic contact to the silicon for any type device.