Sic Sbd And Mesfets Power Device Research

With the increase of the demand of high current capacity,high breakdown voltage and high package density,the development of device based on silicon approached their theoretical limits.With its superior properties such as wide band-gap,high critical breakdown electrified,high thermal conductivity and high saturation carrier drift velocity,Silicon Carbide had good high temperature characteristic,extreme breakdown voltage capacity,high frequency performance,current density and low conductance loss,which is considered to be the hotspot in the semiconductor recently.Based on the SiC material,researchers released different device structures.4H-SiC SBD had low forward voltage,high speed,and make the device had low power loss,even if it had big leakage current,which is used proverbially in smart power system.4H-SiC MESFETs had extraordinary potential in military microwave power system.However, due to the square relation between breakdown voltage and conductance resistance,that how to trade off between improving breakdown voltage and decreasing conductance resistance,that how to modulate electrified became hot topic that researchers pad attention to.This thesis utilizes breakdown theory,new device and stimulation,and releases a novel 4H-SiC anode recessed D-RESURF SBD,optimizes several floating metal strips(FMS),based on silicon power device under the guidance of RESURF principle and junction terminal technology.1.It is necessary to make research of the numerical analysis software in order to reduce error between simulation results and real results.Convergence was a big problem for the absence of SiC parameters and models.This paper introduces numerical analysis,discusses the resolutions and verification.2.This paper proposes a novel Anode-Recessed D-RESURF Schottky Barrier Diode structure based on the 4H-SiC material.The Anode-Recessed trench increase electrified,speed up drift area's depletion,it utilizes D-RESURF technology to improve breakdown voltage and forward conductance performance.The device's thickness,concentration and length are optimized by two-dimensional numerical simulator ISE.Comparing with the Single-RESURF structure,the breakdown voltage of structure proposed increase from 1672V to 890V,decrease forward voltage from 4.4V to 2.8V,conductance current is 80mA/mm.3.This paper makes research about the effects of several metal strips,obtains breakdown voltage,surface electrified and potential contour of single FMS and double FMS structures under different dimensions.The optimized results showed that the breakdown voltage of the 4H-SiC MESFETs with two strips and one strip are 405V and 280V compared to the conventional one without FMS and meanwhile maintain almost same saturation drain current.Moreover,the introduce of FMS increase number of shunt capacitance,worsen the frequency performance,however,it is not affect RF application.