Surface Acoustic Wave Excitation on SF6 Plasma Treated AlGaN/GaN Heterostructure

We present a new modified approach in the forming of interdigital transducers (IDTs) on AlGaN/GaN heterostructure fully compatible with the process technology of HEMTs. The modified approach uses a shallow recess-gate plasma etching of AlGaN barrier layer in combination with "in-situ" SF₆ surface plasma treatment under Schottky gate fingers of IDTs. It enables to excite surface acoustic wave (SAW) in the AlGaN/GaN heterostructure without any high external bias voltages needed to apply to the IDTs. The initial results in the process technology and characterization are presented.