Neutral base recombination in advanced SiGe HBTs and its impact on the temperature characteristics of precision analog circuits

Abstract

We present the first comprehensive investigation of neutral base recombination (NBR) in advanced UHV/CVD SiGe HBTs, and quantitatively assess its impact on the temperature characteristics of precision analog circuits. We show that a direct consequence of NBR in SiGe HBT's is the degradation of Early voltage (V/sub A/) when transistors are operated with constant current input (forced-I/sub B/). We quantitatively address the impact of NBR on precision SiGe analog circuits by incorporating the effect into a new version of SPICE, calibrating the SPICE models to data, and simulating different types of precision current sources across the temperature range of -55/spl deg/C to 85/spl deg/C.