A Snapback-Free and Low-Loss Shorted-Anode SOI LIGBT With Self-Adaptive Resistance

摘要

A novel 600-V snapback-free and low-loss shorted-anode (SA) silicon on insulator lateral insulated gate bipolar transistor (LIGBT) with self-adaptive resistance (SAR) in anode is proposed and investigated by simulation, named SAR LIGBT. The device is characterized by dual anode trenches which are filled with p-type polysilicon and surrounded by oxide, and the dual trenches are shorted with the anode electrode, separated by the low-doped N-region and N+ anode region. At low anode voltage (V-A), the N- region is fully depleted by p-type polysilicon, serving as a large resistance to hinder electrons flowing into the N+ anode; at high VA, an electron accumulation layer is formed along the anode trenches to provide a low-resistance path for electron current. Consequently, N-region makes the distributed resistances at the anode side (RSA) act as a SAR. It not only eliminates the snapback effect but also reduces on-state voltage drop (V-ON) and turn-off energy loss (E-OFF). Therefore, SAR LIGBT achieves a better tradeoff between V-ON and E-OFF. At the same V-ON, the SAR LIGBT reduces the E-OFF by 20.6%, 28.1%, and 30.5% compared with those of multisegment anode, segmented trenches in the anode, and SA-NPN LIGBTs, respectively. Moreover, the SAR LIGBT exhibits the lowest V-ON of 1.71 V and the shortest switching time of 93 ns at J(A) = 100 A/cm(2). In addition, the SAR LIGBT achieves snapback-free with smaller cell pitch than that of separated SA LIGBT.