蓝宝石衬底表面SiO2薄膜的应力分析

INVESTIGATION OF THE STRESS OF SiO_2 FILMS DEPOSITED ON SAPPHIRE SUBSTRATE

采用射频磁控反应溅射法分别在Si和蓝宝石衬底上沉积SiO_2薄膜。通过改变沉积薄膜的工艺参数,考察反应气体流量比、沉积温度、射频功率等因素对SiO_2薄膜内应力的影响。采用压痕裂纹法分析了镀膜前后蓝宝石的表面应力。结果表明:制备SiO_2薄膜时,工艺参数影响SiO_2薄膜的成分,当O_2/Ar流量比值为1.25,衬底温度为300℃,射频功率为100 W时,可以制备出化学计量比的SiO_2薄膜,此时薄膜中的内应力较小;制备的SiO_2薄膜呈压应力状态,镀SiO_2薄膜可以改变蓝宝石的表面应力,蓝宝石的表面应力已由原来的拉应力变为压应力。

SiO2 coatings were deposited on single crystal Si and sapphire substrate by the radio-frequency magnetron reactive sputtering. The influences of the process parameters such as gas mass ratio, deposition temperature and radio frequency power, on the internal stress of SiO2 films were investigated. Surface residual stress of sapphire substrate and the sapphire coated with SiO2 films were estimated using pointed-indentation cracking under Vickers indenters. The results show that the composition and stress of SiO2 films are affected by the process parameters. When the flow ratio of 02 to Ar is 1.25, at a substrate temperature of 300 ℃ and radio frequency power of 100 W, stoichiometric ratio SiO2 films with minimum internal stress can be obtained. The SiO2 films possess compressive stress and so they can change the residual stress of the sapphire surface, i.e., from tensile stress to compressive stress.