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SiO2 薄膜由电子束蒸发方法沉积而成。用GPI数字波面光学干涉仪测量了不同沉积条件下玻璃基底镀膜前后曲率半径的变化,并确定了 SiO2 薄膜中的残余应力。在其他条件相同的情况下,当沉积温度由 190 ℃升高到350 ℃时,SiO2 薄膜中的压应力由-156 MPa增大为-289 MPa。氧分压由3.0×10-3 Pa升高到13.0×10-3 Pa时,SiO2 薄膜中的应力由-223.5 MPa变为20.4 MPa。通过对薄膜折射率的测量,发现薄膜的堆积密度随沉积条件的改变也发生了规律性的变化。应力的变化主要是由于沉积时蒸发粒子的动能不同,导致薄膜结构不同引起的。同时,在样品的存放过程中,发现随着存放时间的延长,薄膜中的应力表现出了由压应力状态向张应力状态演变的趋势。
SiO2 thin film deposited by electron beam evaporation method. The changes of the radius of curvature before and after the glass substrate coating under different deposition conditions were measured by GPI digital wavefront optical interferometer and the residual stress in the SiO2 film was determined. Under the same conditions, the compressive stress in SiO2 film increased from -156 MPa to -289 MPa when the deposition temperature increased from 190 ℃ to 350 ℃. When the partial pressure of oxygen increased from 3.0 × 10-3 Pa to 13.0 × 10-3 Pa, the stress in the SiO2 film changed from -223.5 MPa to 20.4 MPa. By measuring the refractive index of the film, it was found that the bulk density of the film also changed regularly with the deposition conditions. The change of stress is mainly caused by the different kinetic energy of the evaporated particles during deposition, resulting in the different film structure. Meanwhile, during the storage of samples, it was found that with the extension of storage time, the stress in the film showed a tendency of changing from compressive stress to tensile stress.