The interpretation of the p3/2spectra of group III acceptors in silicon

Abstract
The p3/2 energy levels of the hydrogen-like single acceptor in silicon are calculated down to 1.4 meV from the valence band using a non-variational method. The oscillator strength of the transitions from the ground state to the excited states are calculated using an acceptor-dependent ground state wavefunction. A comparison is made with new high-resolution experimental data for group III acceptors B, Al and In. It shows that few of the predicted transitions are not observed and that the relative intensities of the lines are in reasonable agreement with the oscillator strengths. This allows an unambiguous assignment of the lines to specific transitions when the observed peaks can be resolved into individual transitions, and this constitutes an improvement over the existing situation. The calculated values of the highly excited energy levels are very close to the observed ones, but small differences due to chemical shift are found for these highly excited states. Calibration coefficients for the acceptor concentrations can be derived from the oscillator strength calculations and they are compared with those determined experimentally. The most shallow effective mass excited states observed have binding energies of approximately 0.8 and 1.0 meV for B and Al respectively.