A new LIGBT structure to suppress substrate currents in a junction isolated technology

In this paper, a new lateral insulated gate bipolar transistor (LIGBT) structure is proposed to suppress substrate currents in a junction isolated technology by using two buried layers on top of each other. This structure not only allows to reduce the substrate to anode current ratio to less than 10−7, it also yields a device with a large safe operating area and a fast turn-off. Because of the two buried layers, the proposed LIGBT can be used as a floating (above substrate potential) device. Furthermore, the LIGBT is introduced in an existing 80 V smart power technology without the costly need of defining new layers. It has also been shown that the proposed LIGBT can compete with vertical DMOS (VDMOS) devices when used as a large driver. Together with an equivalent circuit, two dimensional simulation has been used to explain the observed device's substrate current behaviour.