Scalable Vertical GaN FETs (SV- GaN FETs) for Low Voltage Applications

Abstract

This is the first report on a novel multi-polarization channel applied to realize normally-off and high- performance vertical GaN device devices for low voltage applications. This structure is made with 2DHG introduced to realize the enhancement mode channel instead of p-GaN as in conventional vertical GaN MOSFETs. As the 2DHG depends upon growth conditions, p-type doping activation issues can be overcome. The Mg-doped layer is only used to reduce the short-channel effects, as the 2DHG layer is too thin. Two more 2DEG layers are formed through AlGaN/GaN/AlGaN/GaN polarization structure, which minimizes the on-state resistance. Simulation analysis shows that this proposed structure can provide a large drain current at ~ 500 𝑚𝐴/𝑚𝑚 level. The calculation results show this novel vertical GaN MOSFET – termed as SV GaN FET - has the potential of breaking the GaN material limit in the trade- off between area-specific on-resistance (𝑅(𝑜𝑛,𝑠𝑝)) and breakdown voltage at low voltages.