DETERMINATION OF DEEP-LEVEL PARAMETERS BY ISOTHERMAL DEEP-LEVEL TRANSIENT SPECTROSCOPY WITH OPTICAL-EXCITATION

A modified isothermal deep level transient spectroscopy method, where the electrical excitation pulse is replaced by an optical one, is intr oduced. Results received by three measuring methods -modifications of DLTS (MCTS, IDLTS, and IDLTS with optical excitation) of measuring two deep energy levels on identical samples (Schottky barriers on epitaxi al GaAs layer grown on bulk n-GaAs by VPE) are compared. It is shown t hat the data extracted from all three measuring methods are practicall y the same for the dominant electron trap (EL2 in all cases). It is mo re complicated to get correct results for hole traps (minority carrier traps). The peculiarities of all the measuring methods are discusscd from this aspect and the results are compared. After having applied a non-exponential mathematical analysis, our modified IDLTS with optical excitation gives the most reliable results in this case.