PHONON ASSISTED TUNNEL EMISSION OF ELECTRONS FROM DEEP LEVELS IN GAAS

A theory is developed for the electric field emission of electrons from deep levels in GaAs taking into account quantum mechanical tunneling and electron phonon interaction. Using this theory, a numerical model is developed simulating capacitive DLTS and capacitive transient experiments. The parameters of the model for the electron irradiation induced defect E3 are extracted by fitting an experimental DLTS spectrum and an experimental transient capacitance curve. In particular, an estimate is given for the Franck-Condon shift. This estimate is found to be consistent with that obtained by another method based on the measured activation energy of the capture cross-section. With the parameters thus found, the model is shown to reproduce correctly several other experimental results over a wide range of temperatures and electric field intensities.