Low-Loss 800-V Lateral IGBT in Bulk Si Technology Using a Floating Electrode

Abstract

An 800V rated lateral insulated-gate bipolar transistor (LIGBT) for high frequency and low-cost applications is proposed. This LIGBT features a new method of adjusting the bipolar gain by using floating N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> regions connected by a floating electrode in front of the P <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> collector. This floating structure lowers the injection efficiency at the collector side of the device, resulting in a very significant decrease in turn-off time and substantially lower turn-off losses. The device was fabricated in a 0.5μm bulk silicon CMOS technology at a commercial foundry without additional processing steps or process optimisation. Tests on fabricated devices showed equivalent Rdson below 70 mQ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 125 °C with switching times as low as 250 ns at 125 °C. The novel LIGBT device showed avalanche capability and low gate capacitance and was used for the first time, in an AC/DC converter operating at 200 kHz allowing significant improvements in performance, compactness, and reduced component count.