Research On IGBT Characteristics Influenced By Horizontal Structure Parameters

IGBT is short for Insulated Gate Bipolar Transistor. Because of its high input impedance, low loss, fast switching speed, low on-state voltage drop-out and large on-state current, IGBT has become the mainstream product in the field of power components and been used in numerous fields. The domestic market demand of IGBT is huge. Although there are some mature processes in China, they cannot implement IGBT by themselves which means they have to import plenty of IGBT to meet the market demand. This weak point hinders the development of power electronics therefore it is important to research IGBT structure parameters.In this paper, the width of gate is optimized by minimizing the on-state voltage drop and the test result provides reference in designing IGBT cell. The characteristics of past IGBT structure and the principle of basic IGBT are also discussed in this paper. The simulation of IGBT based on Atlas of Silvaco software suit. The structure of IGBT is generated by design rule of breakdown voltage and then the I-V characteristics of IGBT with different structure and different voltage ranking is simulated. Based on these simulation results, the IGBT output characteristics difference of both PT and NPT structures are discussed by implying MOSFET-PIN analyzing model, the analysis results show that the state of IGBT PT structure pressure drop is small, the extraction of current density distribution and MOSFET-PIN model analysis results are in agreement. And the IGBT on-state voltage drop of different gate sizes are abstracted under the same current density, also the on-state voltage drop vs. gate width curve is concluded and the simulation result coordinates with the theoretical analysis. This paper then focuses on the reason why the on-state voltage drop changed according to the variation of gate width. Considering the latch-up abilities of each cell layout, the linear cell layout has higher latch-up current, so the gate width of 600V and 1200V IGBT device which is composited linearly is optimized. The optimization results show that the best gate width of these two IGBT is 12μm when the on-state voltage drop gets the minimum voltage. Inclusion as for the same size of IGBT cell, there is a best optimized value of gate width. So it is possible to decrease the on-state voltage drop efficiently by choosing gate width properly. In addition, although the rated voltage could be changed, it is suitable for all plate-gate structure with same cell layout.