Abstract: Insulated gate bipolar transistor (IGBT) is usually used in combination with power diode in power electric circuit because it has no reverse blocking ability. In order to reduce cost and parasitic inductance, the freewheeling diode and IGBT are integrated by process method, and a reverse blocking insulated gate bipolar transistor (RB-IGBT) is thus proposed. For reducing the terminal area of conventional reverse blocking IGBT, an improved composite terminal structure is proposed. The double doped field limiting ring is used to introduce a n-type low doping region near the p-type field limiting ring, which can reduce the lateral expansion rate of depletion region, increase device reliability, improve terminal efficiency and save terminal size.