Ultrafast and Low-Turn-OFF Loss Lateral IEGT With a MOS-Controlled Shorted Anode

Abstract

A novel ultrafast and low-loss lateral injectionenhanced gate transistor (LIEGT) is proposed and investigated by simulation. The device features a MOS-controlled shorted anode (MCSA) and a bias voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AG</sub> ) applied between the anode trench gate (ATG) and the anode electrode. The n+ anode is shorted to the N-buffer through the MOS channel around the ATG when the MCSA is activated with V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AG</sub> V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> during turn-off and blocking states, and thus the p+ anode/N-buffer junction is unactivated. The MCSA LIEGT turns off as fast as a unipolar device by optimizing the time gap to activate the MCSA before turning off the cathode trench gate (CTG). The activated MCSA would deactivate hole injection from the anode side and synchronously quickly extract the electrons from the N-drift, which improves the switching speed and dramatically decreases the turn-off energy loss (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ). In the blocking state, the MCSA LIEGTachievesa MOS breakdown mode instead of an open base p-n-p bipolar breakdown mode. Thus, the breakdown voltage (BV) is not only improved but also independent of the p+ anode doping concentration. In the forward conduction state with V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AG</sub> = 0, the MCSA is unactivated and hence the MCSA LIEGT operates like a conventional LIEGT without deteriorating the on-state voltage drop (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ). Compared with the conventional LIEGT, the proposed device decreases E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> by 88% and improves the BV by 13% at the same VON. Importantly, E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> is almost independent of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> .