Study on the effect of diamond layer on the performance of double-channel AlGaN/GaN HEMTs

The thermal effect is an important reliability issue for GaN-based devices. The impact of the diamond layer on double-channel AlGaN/GaN HEMTs (DC-HEMTs) is first investigated in this paper by Sentaurus TCAD simulation. By utilizing the diamond layer, the lattice temperature along the channel can be modulated and becomes more even. The results show that the peak lattice temperature can be reduced by 64 K when the power dissipation increases to 46 W mm(-1) in the DC-HEMT with a diamond layer. A 1 mu m thick diamond layer is regarded as the optimized thickness when considering the temperature reduction and cost. With the help of the diamond layer, the saturated drain current and transconductance of DC-HEMTs are increased by 0.21 A mm(-1) and 22 mS mm(-1), respectively. Meanwhile, peak f(T) and f(max) can be enhanced by 4.7 GHz and 10.3 GHz, respectively. These results show that diamond layers have great potential in lattice temperature reduction and performance and reliability improvement of DC-HEMTs.