Mechanical Stress in Thin Films.
Abstract
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 dyne/sq cm range. Strong stress (up to 10 to the 10th power dyne/sq 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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1981
- Accession Number
- ADA099311
Entities
People
- D. Mayer
- M. Pedinoff
- Rashaunda Henderson
Organizations
- HRL Laboratories