Research Progress on High-k Gate Dielectrics Materials for 4H-SiC Based Power Devices
Metal-oxide-semiconductor field effect transistor(MOSFET)as a typical device of silicon carbide insulate gate sturcture is one of the most widely applied devices for 4H-SiC.However,the low dielectric constant of gate oxide(SiO2)and poor interface characteristics of SiO2/4H-SiC limits further application of 4H-SiC insulated gate structures(metal-insulator-semiconductor,MIS).Therefore,the research on high-k gate dielectrics which is able to substitute or compensate for SiO2 has attracted extensive attention.This paper reports several key areas on this issue to obtain a better understanding of potential high-k gate dielectrics.Firstly,an ideal gate dielectric materials for 4H-SiC would have large bandgap,high dielectric constant,good interface with 4H-SiC and favorable thermal stability.And the several methods are summarized to evaluate the structural,electrical and interface properties of gate dielectric materials.Furthermore,this paper assesses the current status of these dielectrics and their processing in terms of gate preparation,deposition temperature,interfacial properties and electrical performance,including HfO2,Al2O3,AlN,Y2O3,CeO2,ZrO2,La2O3,Ta2O5,BaTiO3,Ho2O3 and gate dielectric stacks composed of them.Finaly,based on an extensive survey on high-k gate dielectrics for 4H-SiC devices,a future perspective is provided with regards to gate leakage current mechanism,more efforts on varied materials and device viability in harsh environment.
4H-SiC MOS capacitorhigh-k gate dielectric materialgate dielectric stackinterfacial propertyelectrical performance
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