Thin-drift-layer n-channel 4H-SiC IGBT with low switching loss and switching ringing reduction. (1st August 2022)

• Record Type: Journal Article
• Authors: Watanabe, Naoki; Yoshimoto, Hiroyuki; Mori, Yuki; Shima, Akio
• Is Part Of: Japanese journal of applied physics. Volume 61:Number 8(2022)
• Publication Date: 2022-08-01
• Subjects: silicon carbide -- insulated gate bipolar transistor -- switching loss -- switching ringing -- drift layer; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/ac7992
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: An n-channel 4H-SiC insulated-gate bipolar transistor (IGBT) with an extremely low switching loss was demonstrated by making 70 μ m thin drift layers designed for 6.5 kV blocking voltage, without substrates. A conductivity-modulated bipolar operation was successfully performed as a on-voltage of 4.96 V at a 100 A cm −2 collector current. The turn-off losses under 3.6 kV/32 A operation were 8.8 (at room temperature) and 22.7 mJ (at 150 °C), which were much lower than the estimated losses of SiC IGBTs with thick drift layers. A detailed investigation on turn-off transition of SiC IGBTs specifically focused on a voltage-slope increase was also conducted. This phenomenon can cause ringing in switching characteristics. A device structure has been proposed to eliminate it by controlling the expansion of a depletion layer. Voltage-slope control and ringing reduction without noticeable degradation in static characteristics and switching loss were demonstrated with the SiC IGBT with the proposed device structure.