High speed Si PBT with buried single crystal silicide electrode by MBE

Abstract

Silicon permeable base transistors (PBTs) with buried single-crystal electrodes were fabricated by developing formation techniques using molecular beam epitaxy (MBE) for obtaining single-crystal-Si/silicide/Si double-heterostructures and silicide films in submicron size patterns. A high transconductance of 50 mS/mm and high current density of 2*10/sup 4/ A/cm/sup 2/ were obtained. The highest unity current gain frequency (f/sub T/) 6 GHz. Computer simulations indicated that the value of f/sub T/ was reasonable and could be improved by more than one order of magnitude (about 120 GHz) by optimizing the device structure.<>