Relationship between thermal stress and structural properties of SrF2 films on (100) InP

The measurement of thermal stress of SrF₂ films on InP as a function of temperature is presented. The in situ and ex situ rapid isothermal annealed films have different values of thermal stress at room temperature and show entirely different behavior of thermal stress during heating and cooling cycles. X-ray photoelectron spectroscopy measurements were used to characterize the surface of the SrF₂ films as well as the SrF₂/InP interface for both the ex situ and in situ annealed films. It is shown that the difference in the microstructure of in situ and ex situ rapid isothermal annealed SrF₂ films on InP is indeed reflected in the significant difference in the thermal stress.