New Al0.25Ga0.75N/GaN high electron mobility transistor with partial etched AlGaN layer

•The two-dimensional electron gas (2DEG) density in HEMTs is changed by partially etching the AlGaN layer.•With the same device dimensions, the breakdown voltage can be improved by 58% for the proposed Al0.25Ga0.75N/GaN HEMT compared with the conventional structure.•The current collapse can be reduced resulting from the uniform surface electric field.

In this letter, a new Al0.25Ga0.75N/GaN high electron mobility transistor (HEMT) with the AlGaN layer is partial etched is reported for the first time. The two-dimensional electron gas (2DEG) density in the HEMTs is changed by partially etching the AlGaN layer. A new electric field peak is introduced along the interface between the AlGaN layer and the GaN buffer by the electric field modulation effect. The high electric field near the gate in the proposed Al0.25Ga0.75N/GaN HEMT is effectively decreased, which makes the surface electric field more uniform. Compared with the conventional structure, the breakdown voltage can be improved by 58% for the proposed Al0.25Ga0.75N/GaN HEMT and the current collapse can be reduced resulting from the more uniform surface electric field.