论文部分内容阅读
采用电子束蒸发沉积方法在BK7玻璃基底和熔融石英基底上沉积了HfO2薄膜,研究了不同沉积温度下的应力变化规律。利用ZYGO干涉仪测量了基片镀膜前后曲率半径的变化,计算了薄膜应力。结果发现在所考察的实验条件下HfO2薄膜的残余应力均为张应力,应力值随沉积温度的升高先增大后减小。两种基底上薄膜的残余应力的主要产生机制不同。对于BK7玻璃基底HfO2薄膜的残余应力起决定作用的是内应力,熔融石英基底上HfO2薄膜的残余应力在较低沉积温度下制备的薄膜起决定作用的是热应力,在沉积温度进一步升高后内应力开始起决定作用。通过对样品的X射线衍射(XRD)测试,发现在所考察的温度范围内,HfO2薄膜的结构发生了晶态转换,这一结构转变与薄膜残余应力的变化相对应。两种基底上薄膜微结构的演变及基底性能差异是两种基底上薄膜应力不同的主要原因。
HfO2 thin films were deposited on BK7 glass substrates and fused silica substrates by electron beam evaporation deposition, and the stress changes under different deposition temperatures were studied. ZYGO interferometer was used to measure the change of radius of curvature of substrate before and after coating, and the stress of film was calculated. The results show that the residual stresses of HfO2 films are all tensile stress under the experimental conditions investigated, and the stress values first increase and then decrease with the increase of deposition temperature. The main mechanism of the residual stress of the films on both substrates is different. Residual stress on the HfO2 thin film of BK7 glass substrate is determined by the internal stress. The residual stress of the HfO2 thin film on the fused silica substrate is determined by the thermal stress at the thin film prepared at the lower deposition temperature. After the deposition temperature is further increased Internal stress begins to play a decisive role. Through the X-ray diffraction (XRD) measurement of the sample, it was found that the structure of the HfO2 film undergoes a crystal transition within the investigated temperature range, and this structural transition corresponds to the change of the film residual stress. The evolution of the microstructure of the two substrates and the difference of the substrate performance are the main reasons for the different film stresses on the two substrates.