Characterization of multiple deep level systems in semiconductor junctions by capacitance measurements

Capacitance and conductance of junction devices are modified by deep lying impurities in the semiconductor and should therefore in principle be useful for determining deep level parameters, viz, the concentration, the depth of the energy level from the conduction band and the capture cross section of the impurity species present. However, the presence of deep lying impurities in junction devices has been frequently ignored because of difficulties in handling the problem. We show that when deep lying impurities act as majority carrier traps expressions for capacitance and conductance (imaginary capacitance) can be obtained as a solution of a simple different equation.