Improvements in the determination of interface state density using deep level transient spectroscopy

Deep level transient spectroscopy (DLTS) in the current transient mode has been applied to the measurement of the trap density at the silicon-silicon dioxide interface. Application of Shockley–Read–Hall theory to the analysis of DLTS data indicates that if the energy dependence of the majority carrier capture cross section is strong, then it is necessary to take it into account if accurate interface state density values are to be obtained. We have used the small pulse trap filling technique to estimate the degeneracy factor and measure the capture cross sections of the interface states, and then applied this information in the calculation of the interface trap density from a conventional large pulse DLTS temperature scan. Very good agreement is obtained with the values extracted from high-low frequency capacitance-voltage measurements.