退火对HfO2/SiO2多层膜残余应力的影响

用电子束蒸发方法在BK7基底上沉积了HfO2/SiO2多层膜。研究了200℃到400℃的退火对残余应力的影响。结果表明退火前的薄膜残余应力为压应力，在200℃退火后发展为张应力，然后张应力值随着退火温度的升高而增大。在400℃退火后，由于张应力太大，薄膜表面出现了裂纹。同时，随着退火温度的升高，晶粒尺寸长大，晶面间距降低。残余应力的变化与结构的演变相对应。

HfO2/SiO2 multilayer films were deposited on BK7 glass substrates by electron beam evaporation method. The effects of annealing at the temperature between 200 and 400 degrees C on residual stresses have been studied. It is found that the residual stress of as-deposited HfO2/SiO2 multilayers is compressive. It becomes tensile after annealing at 200 degrees C, and then the value of tensile stress increases as annealing temperature increases. And cracks appear in the film because tensile stress is too large when the sample is annealed at 400 degrees C. At the same time, the crystallite size increases and interplanar distance decreases with the increase of annealing temperature. The variation of residual stresses is corresponding with the evolution of structures.