Suppression of boron transient enhanced diffusion in SiGe heterojunction bipolar transistors by carbon incorporation

Abstract

In this work, we demonstrate that the incorporation of carbon in the base of a npn Si/SiGe/Si heterojunction bipolar transistor dramatically reduces the outdiffusion of boron from the base under postgrowth implantation and annealing procedures. Without the addition of C, these processes would lead to transistors with vastly degraded transistor characteristics. This reduction in B diffusion, when compared to devices without C, has been observed by both secondary ion mass spectroscopy and improved electrical characteristics.