Study on a novel vertical enhancement-mode Ga_(2)O_(3) MOSFET with FINFET structure

A novel enhanced mode(E-mode)Ga_(2)O_(3) metal-oxide-semiconductor field-effect transistor(MOSFET)with vertical FINFET structure is proposed and the characteristics of that device are numerically investigated.It is found that the concentration of the source region and the width coupled with the height of the channel mainly effect the on-state characteristics.The metal material of the gate,the oxide material,the oxide thickness,and the epitaxial layer concentration strongly affect the threshold voltage and the output currents.Enabling an E-mode MOSFET device requires a large work function gate metal and an oxide with large dielectric constant.When the output current density of the device increases,the source concentration,the thickness of the epitaxial layer,and the total width of the device need to be expanded.The threshold voltage decreases with the increase of the width of the channel area under the same gate voltage.It is indicated that a set of optimal parameters of a practical vertical enhancement-mode Ga_(2)O_(3) MOSFET requires the epitaxial layer concentration,the channel height of the device,the thickness of the source region,and the oxide thickness of the device should be less than 5×10^(16) cm^(-3),less than 1.5μm,between 0.1μm-0.3μm and less than 0.08μm,respectively.

Design and research of normally-offβ-Ga_(2)O_(3)/4H-SiC heterojunction field effect transistor

Ga_(2)O_(3)is difficult to achieve p-type doping,which further hinders the development of Ga_(2)O_(3)-based power devices and is not conducive to the development of new devices with high power density and low power consumption.This paper expounds aβ-Ga_(2)O_(3)/4H-SiC heterojunction lateral metal–oxide–semiconductor field-effect transistor(HJFET),which can make better use of the characteristics of PN junction by adding p-doped SiC in the channel region.Compared with the conventional devices,the threshold voltage of the heterojunction metal–oxide–semiconductor field-effect transistor(MOSFET)is greatly improved,and normally-off operation is realized,showing a positive threshold voltage of 0.82 V.Meanwhile,the off-state breakdown voltage of the device is up to 1817 V,and the maximum transconductance is 15.3 mS/mm.The optimal PFOM is obtained by simulating the thickness,length and doping of the SiC in each region of the epitaxial layer.This structure provides a feasible idea for high performanceβ-Ga_(2)O_(3)MOSFET.

Two-dimensional subthreshold current model for dualmaterial gate SOI nMOSFETs with single halo

A two-dimensional(2D)model for the subthreshold current in the dual-material gate(DMG)siliconon-insulator(SOI)MOSFET with a single halo is presented.The model considers single halo doping in the channel near the source and a dual-material gate to derive the channel potential using the explicit solution of the 2D Poisson’s equation.Together with the conventional driftdiffusion theory,this results in the development of a subthreshold current model for the novel structure.Model verification is carried out using the 2D device simulator ISE.Excellent agreement is obtained between the calculations and the simulated results of the model.