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Surface Acoustic Wave Excitation on SF6 plasma treated AlGaN/GaN heterostructure

Auteur(s) : T. Lalinsky, I. Ryger, L. Rufer, G. Vanko, S. Hascik, Z. Mozolova, M. Tomaska, A. Vincze

Doc. Source: 12th Joint Vacuum Conference, 10th European Vacuum Conference, 7th Annual Meeting of the German Vacuum Society

Nowadays, there is an increasing interest to generate the Surface Acoustic Wave (SAW) directly on AlGaN/GaN heterostructure material system that defines a two-dimensional electron gas (2DEG) of the high electron mobility transistors (HEMTs). However, the direct interaction of SAW with free carriers of 2DEG prevents the acousto-electric transduction in the interdigital transducers (IDTs) due to the additional insertion losses. Therefore, in this work, we present a new approach in forming of interdigital (SAW) structures on AlGaN/GaN heterostructure to be applied for chemical sensors technology. The new approach uses a selective self-aligned SF6 plasma treatment of the AlGaN/GaN heterostructure to modify 2DEG density thus enabling the redistribution of the E-field and reduction of the peak field in the range of SAW structures. It enables to control these losses, so SAW propagation in the AlGaN/GaN can be observed.