Process for fabricating a bipolar transistor with a thin base and an abrupt base-collector junction

摘要

A process for fabricating a bipolar transistor with a thin base and an abrupt base-collector junction includes the steps of depositing a thin layer of polycrystalline or amorphous silicon base material in a single crystal collector region, while in-situ doping the deposited silicon with boron atoms, and thereafter, recrystallizing the deposited silicon layer by thermal-pulse annealing at a temperature high enough to effect recrystallization and solid phase epitaxial regrowth while low enough to minimize interdiffusion of dopants between the base and collector. The process further includes providing the transistor fabricated by the aforedescribed steps with an abrupt base-emitter junction. This is accomplished by depositing n++ doped polysilicon with a LPCVD process and thereafter thermal annealing the polysilicon.