通孔结构Si衬底AlGaN/GaN HFET的热特性模拟

Modeling on the Thermal Performance of AlGaN/GaN HFET Grown on Si Substrate with Via-Hole Structure

使用有限元软件ANSYS,对通孔结构Si衬底Al GaN/GaN HFET进行了热特性模拟。首先,根据器件结构建立了以栅极为热源的分析模型。然后,通过改变衬底材料、衬底厚度、栅间距以及通孔深度,分别研究了两栅指结构HFET的峰值温度和热阻。最后,对由两栅指结构扩展得到的多栅指结构HFET进行了模拟。结果表明,衬底材料、衬底厚度、栅间距和通孔深度对器件的热特性均有明显的影响,选择合适的参数有利于改善器件的性能;当栅指数目增加时,器件的峰值温度增大,散热趋向于困难。

The thermal performance of a high power AlGaN/GaN HFET grown on silicon substate with via-hole structure was analyzed with the finite-element software ANSYS.First the analysis model,in which the gates were the heat source,was built according to the device structure.Then the peak temperature and thermal resistance of the double-finger HFETs were investigated by changing their substrate materials,substrate thickness,gate spacing and via-hole depth,respectively.Finally,the multifinger devices extended by double-finger structure were studied.It is found that all of factors including substrate material,substrate thickness,gate spacing and via-hole depth have distinct influence on thermal performance of the device and proper parameters choosing will help enhance the device performance,and the peak temperature will rise rapidly when finger number increases which brings more difficulties to heat dissipation.