Study Of Mechanical And Optical Characteristic In Film/substrate System For Dielectric Thin Film

Film is playing an increasing important role in optics field and semiconductor field, therefore it is necessary to improve the quality of film. Study the effect of the film stress on film, especially on sub-nanometer narrow bandwidth filter, could improve the performance of film to a great extent and make it possible to produce super narrow bandwidth filter. It is systematically analyzed in the dissertation that the formation process of film, the model of film stress, the effect of film stress on the formation process of film nucleation, the effect of film stress and heat treatment on the spectrum of dielectric film and the measurement method of film stress. It is concluded through theory analysis and experiment that the ununiformity of film thickness of multilayer film is the main cause of the degeneration of film spectrum on the stress; The substrate bend induced the deviation of incidence angle that cause the inaccuracy of wavelength measurement and increase the insert loss; heat treatment can decrease dielectric film stress, when the heat treatment energy is less than the excitation energy of metastable film only the thermal stress which result in a linear relation between the change quantity of wavelength and the heat temperature is changed, on the contrary, when the heat treatment energy is higher that one, both thermal and intrinsic stress are changed and the change of wavelength is related to time; heat treatment is the contrary process of the reduction of substrate thickness, proper heat treatment temperature can recover the spectrum performance but too high temperature can result in the spectrum degeneration which is also the result of film thickness increases unevenly, the corresponding theoretic formula and relation which determine the proper preparation parameter which can decrease film stress are given; it is considered that heat treatment is one of the primary methods to decrease film stress. The measurement methods of film stress are classified and the merit and the shortcoming of these methods are presented.