A Study of Fast Switching, Anode Shorted Lateral Insulated Gate Bipolar Transistor

In this paper, the performance of a novel anode-shorted Lateral Insulated Gate Bipolar Transistor fabricated using a novel 500 V, 2.5 ¿m digital HV-CMOS process is evaluated for the first time. The process sequence is unique in that it is common for all three technologies viz., the Junction Isolation, conventional Dielectric Isolation and the Double Epitaxial Layer Dielectric Isolation. Unlike the conventional anode-shorted LIGBT, this device has a bipolar turn-on at 0.7 V whilst maintaining fast switching speed. An npn transistor (with the collector-base short) formed within the structure strongly influences the device behavior. The collector-base short of the npn transistor [the same as the anode-short ratio of the pnp transistor] controls the amount of holes injected in the device, which also influences the device turn-off . The influence of the short ratio on the on-state and the turn-off performance is evaluated and the results indicate a favourable trade-off between the turn-off time and the on-state performance of AS-LIGBTs in comparison to the conventional Lateral Insulated Gate Bipolar Transistors.