Modeling of novel RF AlGaN/GaN HEMTs with the structure of n-Si drain extension

In this letter, a novel heterojunction model of RF AlGaN/GaN based high electron mobility transistor (HEMT) combined with n-Si drain extension is proposed and investigated with numerical simulations to decrease the miller capacitance and improve RF power characteristic. Firstly, after verifying the analytical heterojunction model, the simulation model parameters of the traditional HEMTs are extracted by fitting test data of the fabricated device. Then, the extracted model and the n-type silicon structure are combined in the simulation tool to further investigate the mechanism and performance of the proposed HEMTs. It shows that the capacitance effect in the proposed device efficiently reduces by 60% of the original capacitance Cgd. Moreover, the RF characteristic of the proposed device and the traditional device are analyzed, respectively. Both the cut-off frequency and the oscillation frequency of the proposed HEMTs are improved compared to the traditional device and the optimized n-Si width below 0.05 μm. The results show that the proposed device is a potential candidate for high radio frequency (RF) application due to its excellent RF Power properties.