An insulated gate bipolar transistor with a self-aligned DMOS structure

The authors describe a high-performance insulated-gate bipolar transistor (IGBT) with a self-aligned double-diffused MOS (DMOS) structure (SADMOS). A phosphosilicate glass (PSG) sidewall is used to form the n/sup +/ layer and isolate the gate from the emitter electrode. The DMOS structure, including the 5- mu m gap between the polysilicon gates and the small p-layer region under the n/sup +/ layer, is thus fabricated with a completely self-aligned (SA) process. An SA DMOS IGBT with a breakdown voltage of 500 V had a forward voltage drop of 1.6 V at a forward current density of 1100 A/cm/sup 2/, a fall time of 0.2 mu s and dynamic latching current density of 100 A/cm/sup 2/. The forward voltage drop is reduced by 1/3 over that of an IGBT with a conventional DMOS structure.<
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