具有微型倾斜栅场板的高频AlGaN/GaN HEMT器件结构研究

Study of AlGaN/GaN HEMT with micro slant-field-plate gates device structure

较小的器件尺寸可以帮助GaN基HEMT实现更高的频率特性,但会使器件内部电场集聚,引起击穿电压降低,严重限制器件的高频功率特性。为了解决上述问题,采用微型倾斜栅场板,可以在保持频率特性的情况下提升器件的击穿电压。通过对具有不同关键参数(既倾斜角度)的AlGaN/GaN HEMT进行仿真分析,系统研究不同倾斜角度对器件特性的影响。研究发现击穿电压(V_(BK))随着倾斜角度的减小而增大;电流截止频率(f_(T))和最大振荡频率(f_(max))均随着倾斜角度的减小而降低。JFOM(JFOM=f_(T)·V_(BK))随着倾斜角度的减小先增大后降低,具有26.6°倾斜角度的器件的JFOM最大,达到了11.13THz V。通过大信号仿真,发现具有最优倾斜角度的器件工作在深AB类状态时,器件的最大增益、饱和输出功率密度、功率附加效率(PAE)分别为12.90dB、5.62W/mm、52.56%。

Smaller device size can help GaN-based HEMT to achieve higher frequency characteristics,but it will cause the electric field inside the device to concentrate and cause the breakdown voltage to decrease,which severely limits the high-frequency power characteristics of the device.In order to solve the above problem,this paper employs a micro slant-field-plate gate,which can enhance the breakdown voltage of the device while maintaining the frequency characteristics.The effects of different slant angles on the device characteristics are systematically investigated by simulating and analyzing AlGaN/GaN HEMT with different key parameters(slant angles).It is found that the breakdown voltage(V_(BK))increases as the slant angle decreases;the current cutoff frequency(f_(T))and the maximum oscillation frequency(f_(max))both decrease as the slant angle decreases;the JFOM(JFOM=f_(T)·V_(BK))increases and then decreases as the slant angle decreases,and the device with a slant angle of 26.6°has the largest JFOM of 11.13THz V.Through large-signal simulation,it is found that when the device with the best slant angle operates in the deep class AB state,the maximum gain,saturated output power density,and power added efficiency(PAE)of the device are 12.90dB,5.62W/mm,and 52.56%,respectively.