CHARACTERIZATION OF DOMAIN-INVERTED LAYERS IN LITAO3 BY LINE-FOCUS-BEAM ACOUSTIC MICROSCOPY

A characterization procedure of domain-inverted layers employed in LiT aO3 optoelectronic devices by line-focus-beam acoustic microscopy is e xplored. A special specimen of -Z-cut LiTaO3 with a domain-inverted la yer of about 1.8 mu m thickness, processed under the fabrication condi tions for quasi-phase-matching second-harmonic-generation devices, was prepared for measurements of the leaky surface acoustic wave (LSAW) v elocities in the frequency range 100 to 300 MHz. Intrinsic decreases i n LSAW velocity were obtained with the rate of 0.127 m/s/MHz, which we re in excellent agreement with the theoretical results. These resulted from formation of a domain-inverted layer on the -Z surface. Slight v ariations in domain-inverted depth on the specimen, caused by variatio n in process temperature, were also detected, with the measurement res olution of 0.01 mu m at 225 mHz.