Improvement of IGBT latching performance by indium doping

Abstract

Summary form only given. The Insulated Gate Bipolar Transistor (IGBT) has become the dominant power MOS-gated switching device of choice for medium power electronics applications. One of the inherent weaknesses of the IGBT is the presence of a parasitic four-layer npnp thyristor structure that must be suppressed from turning on to retain gate-controlled operation. Several techniques, notably the cell design and counterdoping of the MOS channel, have been proposed to improving the latching suppression, particularly at elevated temperatures. In this paper, a novel latchup improvement technique, which adds indium in the p body region to decrease the sheet resistance of that region under the n/sup +/ emitter without a concomittant increase of threshold voltage, is proposed and demonstrated experimentally.