A Float P-Drift and Blocking Junction LIGBT With Low Turn-Off Loss and No-Snapback

Abstract

To reduce turn-off losses ( $E_{\mathrm {OFF}}$ ) of power devices, a lateral insulated gate bipolar transistor structure with a float p-drift and blocking junction (FPBJ-LIGBT) is proposed and investigated. The blocking junction in the proposed device is formed by embedding a p-drift between the highly doped carrier storage layer and n-drift. Thereby, not only low voltage drop ( $V_{\mathrm {ON}}$ ) is $\cdot $ achieved, but also the breakdown-voltage is not-affected. At the low current on-state, due to extra auxiliary BJTs, the snapback phenomenon of FPBJ-LIGBT is eliminated. At the high current on-state, thanks to working at the conventional LIGBT (C-LIGBT) mode, the FPBJ-LIGBT obtains low $V_{\mathrm {ON}}$ . During turn-off transient, due to auxiliary hole extraction of float p-drift and rapidly established E-field of blocking junction, the $V_{\mathrm {ON}}$ - $E_{\mathrm {off}}$ tradeoff relationship of FPBJ-LIGBT is improved. The simulation results show that, compared with the float p-pillar and reduced surface field (FPR) LIGBT and C-LIGBT, the $E_{\mathrm {OFF}}$ of the FPBJ-LIGBT are reduced by 35% and 30% at $I_{\mathrm {CE}} \; = 100$ A/cm2, respectively. Furthermore, under short-circuit condition, the heat distribution of drift region is improved, so the short circuit capability of FPBJ-LIGBT is improved 66.1% and 62.3% at $V_{\mathrm {CE}} \; = 200$ V compare with C-LIGBT and FPR-LIGBT, respectively.

Keywords

• Electric field
• lateral insulated gate bipolar transistor (LIGBT)
• turn-off losses
• snapback
• short-circuit capability