We present a new approach in forming of interdigital surface acoustic wave-structures on AlGaN/GaN heterostructure to be applied in chemical sensors technology. This approach uses a selective self-aligned SF6 plasma treatment of the AlGaN/GaN barrier layer to modify 2DEG density and surface field distribution in the range of interdigital transducers (IDTs) thus enabling SAW excitation. Secondary ion mass spectroscopy was applied to explain the modification of 2DEG density in the plasma treated AlGaN/GaN heterostructure. The initial results in the process technology and characterization are presented. (c) 2008 Elsevier B.V All rights reserved.