Study Of A Superjunction SOI LIGBT Device

Silicon LIGBTs(Lateral Insulated Gate Bipolar Transistor)have been difficult to satisfy the increasing demand for integrated power semiconductor devices in power semiconductor circuits.Like silicon LIGBTs,SOI(Silicon On Insulator)LIGBT devices have high breakdown voltage and high saturation current.Compared with power BJTs(Bipolar Junction Transistor),they have faster switching speed and simpler driving circuit.At the same time,SOI LIGBTs' buried oxide layer effectively isolate the substrate and drift region,block the carrier leakage path greatly and improve the integrability of LIGBT devices.To realize the high breakdown voltage over 500 V,the thick SOI layer may be selected by using a much thick oxide layer.The thick SOI layer reduces the advantage in isolation,and the thick oxide layer exacerbates the temperature characteristics of the SOI.Therefore,the thin SOI with the linear doping concentration is designed to realize a high breakdown voltage with the enhancd critical electric field.However,the thin SOI layer always induces a degeneration of the saturation current due to the high carrier recombination and the low hole injection caused by the high doping concentration near the anode.In addition,the thick field oxide covering the full region of the thin SOI makes it difficult to improve the saturation current by optimizing the drift region.In this paper,a new type of superjunction SOI LIGBT device is designed,namely Semi-SJ(Semi Superjunction)SOI LIGBT.First,this paper describes the development of power semiconductor devices,IGBT(Insulated Gate Bipolar Transistor)devices,and SOI LIGBT devices.The basic theory,namely the superjunction and enhancd critical electric field,of Semi-SJ SOI LIGBT device design is analyzed.The key parameters of the device are given.The basic characteristics of Semi-SJ SOI LIGBT are described with the simulation of Sentaurus TCAD(Technology Computer Aided Design).The mixed conduction mode of the Semi-SJ SOI LIGBT is described and the mechanism of the mixed conduction mode is described in terms of theory and simulation.Based on the partner process platform,the Semi-SJ SOI LIGBT process flow and the layout design of the Semi-SJ SOI LIGBT device are designed.The carrier storage devices,shorted anode LIGBT devices,and segmented thick oxide devices based Semi-SJ SOI LIGBT are also designed.Their mechanism and layout design are briefly described.The experiment was performed on the process platform provided by the partner.Finally,a semi-SJ SOI LIGBT with 0.17?m thin silicon layer is realized.The saturation current is increased by 38.9% compared to the conventional structure,and the breakdown voltage is up to 850 V,as same as the conventional structure.