Effect of a ferroelectric inversion layer on the temperature characteristics of SH-Type surface acoustic waves on 36/spl deg/ Y-X LiTaO/sub 3/ substrates

Abstract

The temperature coefficient of delay of the SH-type surface acoustic wave on 36 degrees Y-X LiTaO(3) substrates with a ferroelectric inversion layer is theoretically analyzed and it is shown that the temperature characteristics can be improved by an electric-field short-circuiting effect of the domain boundary. The experimental results of the temperature coefficient of delay agree well with the theoretical. The minimum value of measured temperature coefficients of delay is 12.6 ppm/ degrees C for the metallized surface case, which is about one-third of that in a 36 degrees Y-X substrate with no inversion layer. Experimental results on the phase velocity and the electromechanical coupling factor of the SH-type surface acoustic wave are also presented and compared with the theoretical.