Method of determining capture cross section including a slow capture of carriers in the depletion edge region

The capture process of carriers in the pulse-filling measurements is analyzed by including the slow capture on the edge of a depletion layer. An analytical expression is derived to determine the capture cross section of majority carriers from the initial slope of the semilogarithmic plot of capacitance versus capture time in the case of low trap concentration. A method is proposed to determine the fast capture rate in the bulk region from a slow capture process in the edge region when the trap concentration is not negligible compared with the concentration of the shallow dopant. The edge effect is intentionally enhanced to observe the capacitance variation with the capture time. Pulse-filling measurements on Au-doped Si p+n and undoped liquid-encapsulated Czochralski n-GaAs Schottky diodes are made to verify the method.