Effect of Macro-scale Mechanical Stress of Silicon Wafer on Room Temperature Photoluminescence Signals

Mechanical stress was applied to single side polished and double side polished Si wafers in polypropylene wafer containers for different localized stress levels and durations. Room temperature photoluminescence (RTPL) spectra from Si wafers were measured before and after applying localized mechanical stress. Significant changes (up to 26% increase) in RTPL intensity were measured from areas under different stress levels even 1 year after the fixtures for mechanical stress generation were removed. Significant effects of localized mechanical stress on RTPL intensity variations were measured up to 49 days after the fixture removal. Nearly fully relaxed RTPL signatures for localized mechanical stress were measured 450 days after the fixture removal. RTPL intensity is found to be very sensitive to the externally applied macro-scale mechanical stress of Si wafers and residual (or memorized) internal stress even after removal of fixtures for external mechanical stress generation.