Mechanical Stress in Thin Films.
Final technical rept.,
HUGHES RESEARCH LABS MALIBU CA
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A multi-angle ellipsometry technique has been developed. The elements are Measure Delta and Psi for several angles of incidence. Then compare the data with theoretical values which have been calculated from a model that predicts the optical properties for a system comprising several thin film layers on an reflecting substrate. Each film layer has some anisotropy stress and optical constants iterate the model parameters to obtain the best fit with the measured and theoretical values for Delta and Psi. This technique has been applied with success to SiO2 and silicon-on-sapphire thin films. The data reveal a 6 A thick inner layer between the SiO2 film and the silicon substrate. The films have various stress values in the 10 to the 9th power dynesq cm range. Strong stress up to 10 to the 10th power dynesq cm is found in silicon-on-sapphire. Three SOS samples were graded for optical quality - the degree of perfection was inversely related to the amount of stress found. Author
- Optical Detection and Detectors
- Solid State Physics