Comprehensive Monte Carlo simulation of the nonradiative carrier capture process by impurities in semiconductors

The main nonradiative capture mechanisms, cascade and multiphonon emission, have been numerically simulated by the Monte Carlo method. To do so, both mechanisms were included in the frame of a previous numerical procedure to which the nonacoustic-phonon contribution was also added. Different centers were studied. Capture by shallow donors (P, As, and Sb) in n-type silicon were interpreted considering only the cascade process. Capture by acceptors levels of platinum, gold, and titanium in silicon, and one level of Cr, EL2, and EL3 in gallium arsenide, were analyzed considering only multiphonon emission, and calculating the values of Huang-Rhys factor when it is not available. In the study of capture by attractive deep centers, such as single ionized donor centers of sulfur and selenium in silicon, both cascade and multiphonon mechanisms must be combined. In this case the importance of the nonacoustic phonon has been shown in the cascade process.