Combination of optical measurement and precipitation theory to overcome the obstacles of detection limits

Ham's theory was applied in order to become independent of detection limits for oxide precipitates and to quantify the phenomenon of oxygen loss to invisible BMDs during thermal treatments. The density of detectable bulk micro-defects (BMDs) depends on the size distribution of grown-in nuclei and the ramp rate, temperature, and duration of the thermal treatment applied. There is no correlation to the invisible BMDs. During conventional annealing, the density of the invisible BMDs decreases exponentially with increasing radius of precipitates at a nearly constant loss of interstitial oxygen. Only if the calculated radius exceeds 70 nm, a 100% loss of interstitial oxygen to BMDs detectable by scanning infrared microscopy (SIRM) seems to be possible. After RTA processing at 1230 °C, a period of 1 h at 1000 °C would be necessary for the growing oxide precipitates to reach a saturated density detectable by SIRM, but there remains a very high density of invisible BMDs consuming interstitial oxygen. In N-doped silicon, the vast majority of BMDs is detectable by SIRM, cleave and etch, and infrared light scattering tomography after thermal processing.