钽酸锂薄膜溶胶凝胶制备工艺研究

Preparation process of sol-gel derived LiTaO_3 thin films

用溶胶–凝胶法在不同衬底上制备了新的钽酸锂薄膜;研究了环氧树脂掺杂、甩胶转速、衬底效应、热处理温度和气氛等薄膜制备工艺条件对薄膜晶向、表面形貌和介电特性的影响。结果表明:当溶胶浓度为0.1mol/L,转速为3000r/min,能制备出均匀、平整、无裂纹的薄膜;控制掺杂环氧树脂在5%左右(质量分数),能提高薄膜与衬底的黏附性;薄膜在氧气气氛下结晶退火,比在氮气气氛下具有更小的介质损耗;n型Si、p型Si和SiO2衬底上钽酸锂薄膜在[012]晶向上具有择优取向性,而Pt衬底上薄膜在[110]、[116]晶向上具有择优取向性。

LiTaO3 thin films were prepared on different substrates by sol-gel. Effects of the preparation process conditions such as different concentration doped epoxy resin, different speed of spin coating, different substrate, different annealing temperature and atmosphere, on the crystalline orientation, surface morphology and dielectric loss of LiTaO3 thin films were investigated. The results show that the uniform, smooth and crack-free LiTaO3 thin films are prepared using 0.1 mol/L LiTaO3 sol matched with spin coating speed of 3 000 r/min. The 5% epoxy resin doped LiTaO3 sol improves the adhesiveness of films to the substrate. The LiTaO3 films crystallized in oxygen gas have smaller dielectric loss than that in nitrogen gas. The LiTaO3 films on n type Si（100）, p type Si and SiO2 substrate have preferred orientation of [012], while LiTaO3 thin films on Pt/Ti/SiO2/Si（100） have preferred orientation of [110] and [116].