Characterization of Semiconductor Electrodes with a Deep Impurity Level

The relaxation effects of a deep impurity level on the relationship have been discussed. Capacitance was derived as an explicit function of a bias , which gives the characterization method for the semiconductor electrodes such as . Interpretation for the conventional Mott‐Schottky plots must be renewed.If a level lies just below the bulk Fermi level, the plot is approximated by two inflecting straight lines, but the inflection potential does not give precise information about the energy level of a deep level, conventionally accepted. If a level is deep, its relaxation time is so high that the measuring frequency usually used, even when 1 Hz, becomes the high frequency limit. The slope of the plot obtained under a high frequency limit gives quite an erroneous doping concentration. It is pointed out that extremely low frequency must be used to determine the energy level and the doping concentration of a deep level. The presence of the deep level also causes the slope of the plot to be frequency dependent.