Technology related issues regarding fabrication of AlGaN/GaN-based MOSHFETs with GdScO3 as dielectric

Starting out from our well established process for AlGaN/GaN HFETs, the authors discuss ways to enrich the process in order to fabricate metal-oxide-semiconductor HFETs (MOSHFETs) with a gadolinium scandate (GdScO₃) insulation layer. In particular, adequate processing orders, various etching procedures and possible drawbacks of the GdScO₃ deposition process on ohmic contacts are discussed. Making use of the gained knowledge, the authors fabricated GdScO₃-MOSHFETs for the first time. Compared to a conventional HFET the new device shows a higher saturation drain current and a lower gate leakage current. Nevertheless, the potential insulating properties of GdScO₃ are not fully exploited yet and further optimization of the deposition process is needed