FLAT OXIDE PIEZOELECTRIC BOARD, MANUFACTURING METHOD OF OXIDE BOARD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a board having a very flat surface, enabling the realization of a high frequency SAW device or low optical transmission loss type optical application device. SOLUTION: An oxide piezoelectric board having a surface roughness of 0.15nm or less is prepared and pref. made of LiNbO3 or LiTaO3 . The surface of an oxide piezoelectric board or oxide board is made flat pref. by annealing it at a lower pressure than the atmospheric pressure in an oxidative gas atmosphere. The IiTaO3 single crystal substrates(Z-cut) are prepared; fines are etched for 15sec in a 5vol%-hydrofluoric acid water soln. Then, the ten substrates are annealed in various conditions to measure the surface roughnesses before and after the treatment, using an AFM apparatus and the result shows the annealing greatly improved the surface roughness as listed in the table.