Effects of high-injection barrier (HIB) position on bipolar transistor characteristics

This paper analyzes the effects of the vertical position over the n^$collector of the n-type layer formed by a high energy phosphorus implantation on the high current level characteristics of the n-p-n bipolar device. From the device simulation and measurement data, we demonstrate that the barrier located near the buried layer plays a more effective role in the suppression of both the base-widening effect and the avalanche multiplication effect in the high collector current region, whereas the barrier near the intrinsic base achieves base Gummel number reduction and high-current gain at a low collector current level. This paper is also concerned with a quasi-saturation phenomenon found in devices in which the barrier is near the base-collector junction. The factor accounting for this phenomenon is analyzed by way of two-dimensional simulations and measurements