Significant enhancement of electrical behavior of SAW devices on langasite and quartz substrates obtained by improvements in design and technology

This paper presents some improvements applied in design and fabrications of SAW devices manufactured on langasite and quartz substrates. For a best design we limited the number of IDTs pairs to 40, we chose the distance between In and Out of IDTs to be an integer number of wavelengths and we enlarged the finger width with 0.5μm. Optimisation of technology was done by applying the following measures: direct loading of the wafer to sputtering installation, heating the substrate to 150 °C during metallization, limiting the thickness of Cr/Au conducting layer to 10 nm/30 nm and eliminating the short circuits by electric means. A yield close to 90% was obtained. The enhanced electrical behaviour of SAWs was analysed and discussed in detail.