In this paper, a new structure of transistor AlGaN/GaN high electron mobility transistor (HEMT) is presented. The proposed structure is implemented on a regular HEMT layer wafer. In this structure, the creation of a new layer Si3N4 on the initial structure was used to improve the frequency response and the impurity oxide layer to improve the flow efficiency. The proposed structure has a current rate of 140 dB at a cutoff frequency of 800 GHz, which is much improved with respect to the original structure as well as other structures presented in this regard. For a better comparison, two models of HEMT are simulated by the Silvaco TCAD software, which includes a normal HEMT model, and the other incorporating an improved HEMT by adding an impurity layer in it. The proposed simulation of this structure makes it possible to use it in high-frequency circuits.
