Lithium Tetraborate - A New Temperature Compensated Piezoelectric Substrate Material for Surface Acoustic Wave Devices

Abstract

Bulk wave and surface wave device measurements on lithium tetraborate single crystals have indicated that the material shows considerable promise for SAW substrates. Measurements on X-cut, Z-propagating SAW devices have shown a parabolic time delay/ temperature behaviour with the minimum at ll°C combined with a SAW coup1 ing factor of 1.06% (approximately 10 times lar er than ST-Quartz) and a SAW overall variation in time delay of ? 60 ppm from 0 to 4OoC which, while being higher than ST-Quartz over the same temperature range, is considerably smaller than YZ-LiNb03 (? 1880 ppm). temperature stability, combined with the strong SAW coupling, means that it is an ideal candidate for temperature stable SAW filters with bandwidths in the 2 to 5% range. velocity of 3500 ms- 9 . The substrate shows an