Energy concepts of insulator–semiconductor interface traps

A general statistical language developed for impurities and defects in semiconductors has been applied to the interpretation of experimental results from different methods of investigations of insulator–semiconductor interface traps. Interface state energy distributions obtained from traditional capacitance–voltage methods or ‘‘Scanned Light Pulse Technique’’ are interpreted in a Gibbs free energy scale. On the other hand, distributions obtained from Deep Level Transient Spectroscopy (DLTS) are put on an enthalpy scale. The difference between the two parameters depends on the entropy properties of the trap centers. Carrier capture data taken from DLTS are demonstrated to be influenced by the ‘‘entropy factor’’ of the interface trap resulting in discrepancies of capture cross sections of up to two orders of magnitude. It is further pointed out that the energy resolution of experimental energy state distributions is fairly rough for different methods ranging up to 0.1 eV for CV technique at room temperature.