The Study of Improving High Voltage LIGBT Substrate Leakage Current

Abstract

This paper aims to the research of high voltage lateral insulated gate bipolar transistor (LIGBT) and proposes the design for reducing the substrate leakage current of this device. The junction between LIGBT’s p-type substrate and n-epi layer may have a large electrical field and causes the hole current to flow during the turn-on state. To prevent this substrate leakage current, an n-type buried layer (NBL) and a p-type buried layer (PBL) are used. The double reverse biased pn-junction structure effectively reduces the vertical electric field such that the substrate current is reduced by four orders of magnitude. The break down voltage of the LIGBT is not hurt by this added structure at all.