LiNbO_3晶体表面Na^+扩散的理论分析及实验研究

Theoretical analysis and experimental study of Na^+ diffusion into LiNbO_3 crystal wafers

基于扩散方程 ,对LiNbO3 晶片Na+ 扩散进行了理论分析和实验研究。研究表明 ,LiNbO3 晶体的Na+ 扩散工艺宜选择Na2 CO3 和富锂LiNbO3 的混合物为扩散源 ,于 95 0～ 10 0 0℃扩散 2 0h。扩散可一定程度地保证Na+ 的均匀性。扩散层厚度以及Na+ 相对含量和扩散层厚度的关系与扩散时间密切相关 ,且Na+ 扩散进入LiNbO3 晶片的扩散源是相对变化的 ,表层为NaNbO3 ,其次是Li1-xNaxNbO3 ,x值随扩散的深入而变小。同时发现晶片的Na+ 扩散是以Na+ 替代Li+

Based on diffusion equation, the theories, techniques and mechanisms of Na + diffusion into LiNbO 3 crystal wafers were studied for the first time. The study indicated that mixture of Na 2CO 3 and rich lithium LiNbO 3 was appropriate diffusion source for LiNbO 3 crystal wafers and diffusion proceeded at 950～1000℃ for 20h. LiNbO 3 Crystals thus obtained showed better uniformity than that of Na + doped LiNbO 3 crystals. The diffused depth and relation of which with relative content of Na + closely related with diffusion time and diffusion sources varied for Na + diffusion LiNbO 3. The first layer was composed of NaNbO 3, then was Li 1- x Na x NbO 3 and the value of x decreased with that of depth. Meanwhile the diffusions of Na + into LiNbO 3 crystal wafers were proceeded by means of the replacement Li + by Na +.