Si(111)上生长LiNbO_3薄膜的研究

利用射频磁控溅射的方法,在Si(111)衬底上制备了LiNbO3薄膜。采用X射线衍射(XRD)和扫描电子显微镜(SEM)研究了衬底温度、退火温度和溅射气体压强对LiNbO3薄膜结晶和表面形貌的影响,并用椭圆偏振仪测量了薄膜的厚度和折射率。结果表明:衬底温度为450℃时制备的薄膜,退火前后都没有LiNbO3相生成;衬底温度为500～600℃时,LiNbO3薄膜出现(012)、(104)和(116)面衍射峰,经600℃退火后3个衍射峰的强度加强;衬底温度为600℃时,经600～900℃退火得到的LiNbO3薄膜,除出现(012)、(104)和(116)面衍射峰外,还出现(006)面衍射峰;溅射气体压强从0.8 Pa增大到2.4 Pa时,经800℃退火后得到的LiNbO3薄膜表面晶粒团簇变小,而0.8 Pa制备的薄膜经800℃退火后LiNbO3相的结晶程度较其它压强下完善;900℃退火后得到的LiNbO3薄膜折射率为2.25,与LiNbO3晶体相当。

Study of growth of LiNbO_3 film on Si(111) substrate

A rf magnetron sputtering system was used to deposit lithium niobate(LiNbO3) film on Si(111) substrate.The effects of substrate temperature,the annealing temperature and the sputtering gas pressure on the crystallization and the surface morphology of thin films were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The film thickness and refractive index was also measured by an ellipsometry.The results show that the XRD peak of LiNbO3 phase is not present at 450 ℃ substrate temperature,neigher is it after annealed.At 500～600 ℃ substrate temperature,XRD peaks of(012),(104) and(116) planes of LiNbO3 are found,and their intensities increase after annealed at 600 ℃.At 600 ℃ substrate temperature,XRD peak of(006) plane emerges after annealed at 600～900 ℃ with the peaks of(012),(104) and(116) plane.Samller clusters of grains are obtained when the total pressure of the sputtering chamber is increased from 0.8 Pa to 2.4 Pa after annealed at 800 ℃.The best crystallized LiNbO3 phase is obtained under the pressure of 0.8 Pa.The refractive index of LiNbO3 film is 2.25,which is close to that of crystal LiNbO3.