Chu Weili

A simulation study on a novel trench SJIGBT

An overall analysis of the trench superjunction insulated gate bipolar transistor (SJ IGBT) is presented and a detailed comparison between a trench SJ IGBT and a trench field stop IGBT is made by simulating with Sentaurus TCAD. More specifically, simulation results show that the trench SJ IGBT exhibits a breakdown voltage that is raised by 100 V while the on-state voltage is reduced by 0.2 V. At the same time, the turn-off loss is decreased by 50%. The effect of charge imbalance on the static and dynamic characteristics of the trench SJ IGBT is studied, and the trade-off between parameters and their sensitivity versus charge imbalance is discussed.

SPT+-IGBT characteristics and optimization

A novel advanced soft punch through (SPT) IGBT signed as SPT+-IGBT is investigated. Static and dynamic characteristics are simulated based on the 1200 V device structure and adopted technology. Extensive research on the structure optimization of SPT+-IGBT is presented and discussed. Compared with the structure of conventional IGBT, SPT+-IGBT has a much lower collector—emitter saturation voltage and better switching characteristics. Therefore it is very suitable for applications blocking a voltage higher than 3000 V. In addition, due to the improvement of switching speed achieved by using a thinner chip, SPT+-IGBT is also very competitive in 1200 V and 1700 V applications.

A novel optimization design for 3.3 kV injection-enhanced gate transistor

This paper introduces a homemade injection-enhanced gate transistor (IEGT) with blocking voltage up to 3.7 kV. An advanced cell structure with dummy trench and a large cell pitch is adopted in the IEGT. The carrier concentration at the N-emitter side is increased by the larger cell pitch of the IEGT and it enhances the P—i—N effect within the device. The result shows that the IEGT has a remarkablely low on-state forward voltage drop (VCE(sat)) compared to traditional trench IGBT structures. However, too large cell pitch decreases the channel density of the trench IEGT and increases the voltage drop across the channel, finally it will increase the VCE(sat) of the IEGT. Therefore, the cell pitch selection is the key parameter consideration in the design of the IEGT. In this paper, a cell pitch selection method and the optimal value of 3.3 kV IEGT are presented by simulations and experimental results.