The integration of an oxide layer in metal-oxide-semiconductor high electron mobility transistors (MOSHFETs) plays a crucial role in minimizing gate leakage current and enabling wider gate voltage swings. In this study, we present the fabrication and characterization of GaN/AlGaN heterostructure field-effect transistors (HFETs) capped with a Ga₂O₃ dielectric layer. The oxide was deposited via an in-situ process within a single MOCVD reactor without vacuum interruption. Our findings demonstrate that the in-situ capped HFETs exhibit a significantly lower interface charge density of 4 × 10¹² cm⁻² compared to 1 × 10¹³ cm⁻²·eV⁻¹ observed in ex-situ grown counterparts. These results highlight the advantage of in-situ dielectric integration for improved interface quality and device performance.
Tahir et al. (Thu,) studied this question.