The Design Of IGBT With A Hole Blocking Layer

The insulated gate bipolar transistor (IGBT) has the prominent advantages of highbreakdown voltage, low forward voltage drop and so on. And it can be widely used inhigh-voltage and medium-voltage power electronic systems. With the introduction ofthe next generation of products, IGBT is not only gradually replacing the BJT andMOSFET power devices in the consumer electronics, but also replacing the MOSFETand the GTR in the industry. Therefore, the study of IGBT becomes very important.IGBT has a contradictory relationship between the forward voltage drop andbreakdown voltage, so we propose a hole blocking IGBT (HBIGBT) first time in thispaper to deal with contradictory problem. The main innovations are listed as follows:(1) We introduce the basic structure and principles of CSTBT at first, and analyzethe static parameters and dynamic parameters of CSTBT, P-i-N diode and traditionalTrench IGBT by simulation. CSTBT makes a compromise between the forward voltagedrop and breakdown voltage of IGBT. But its N-type barrier layer will affect theblocking voltage of CSTBT, and therefore we need to improve the structure of CSTBT.(2) Based on the CSTBT and MOS/P-i-N Model, we propose a new structurewhich is called HBIGBT. HBIGBT has a hole blocking layer (i.e. the oxide layer)between the P-body region and the N-drift region to replace the N-type barrier layer inCSTBT. Hole blocking layer makes the carrier stored in the N-drift better than N-typebarrier layer, so HBIGBT has a better conductivity modulation effect. Meanwhile, thisis a similar structure of the P-i-N diode in device formed by the P-collector region, theN-drift region, and the hole blocking barrier layer. We get the HBIGBT with thebreakdown voltage of1639V, the forward voltage drop of1.59V and turn-off time of1735ns by simulation and the optimization parameters of the hole blocking layer. Wealso propose some improved structures to deal with the contradictory relationshipbetween the forward voltage drop and breakdown voltage and to develop the turn-offtime of device. Just like positive improved structure (i.e. intermittent hole blockinglayer), internal improved structure (i.e. N-type barrier layer in the bottom of the N-driftregion) and back improved structure (i.e. double short anode IGBT) for the dynamic characteristic improvement. All advantages make the HBIGBT has the better staticparameters and dynamic parameters than CSTBT, and provide a reference for the designof high-voltage IGBT.(3) Combined with the technology of the field limiting rings and field plates, wedesign the junction termination of which can blocking breakdown voltage of1200V. Atlast,we get the junction termination of which can blocking breakdown voltage of1470Vthrough the simulation analysis. Based on the structure and process of HBIGBT, we getthe layout of the HBIGBT and make a foundation for device manufacturingimplementation.