Study Of AlGaN/GaN Power Device Based On Energy Band Modulation Technology

As wide band gap semiconductor, AlGaN/GaN based power device becomesinternational research focus in power switching and power rectifiering because of itshigh voltage withstanding ability and low on state resistance. The negative ionimplantation in the HFET channel can modulate the band gap, as well as changing thefree electron density at the heterostructure interface. In that sense, the band gapmodulation technology based on that technology can effecitvely offer theoretical basisfor revising the device threshold voltage, decreasing the gate leakage current, makingjunction termination extension(JTE) region.this thesis focus on the problems mentioned above, discuss the power switchingdevice based on band gap modulating technology. Intense discussion and research isconducted on the designing and optimization of the reduce surface electricfield(RESURF) region based on negative ion implantation, establishment of the bandgap modulation model and gate forward leakage current reduction based on band gapmodulation model.1. Test the working mechanism of the negative ion implantation on voltagewithstanding of the power devices. First, obtain the simulation optimization designstructure through simulation analysis. It contains implantation of negative ion at thedrain side gate edge to extend junction termination extention(JTE) in powerAlGaN/GaN HFET. The negative ion is implanted with different doping concentrationof even dopant and different junction JTE length to form even electric field distribution.This is testified by experiment.2. Establishing the AlGaN/GaN heterostructure band gap structure modulationmodel aroused by negative ion implantation, obtain implantation electron dopant andenergy band distribution analysis formula in barrier layer and at heterostructureinterface. Meanwhile, through numerical analysis by simulation software, discussdifferent negative ion modulating effect on energy band. Compare the analytical result,the numerical result and experiment result and obtain an accurate analytical model.Thus it offers theoretical basis for leakage current reduction in the barrier layer and modulation of the2DEG density in the channel.