ELECTRICAL CHARACTERISTICS AND DEEP-LEVEL ADMITTANCE SPECTROSCOPIES OF LOW-TEMPERATURE-GROWN GAAS P-I-N STRUCTURES

The properties of low-temperature grown GaAs are studied via the elect rical characterization of p-i-n structures with part of the intrinsic layer grown at 300 degrees C. Comparisons are made between the low-tem perature and normally grown samples. The current of the low-temperatur e sample is about two orders of magnitude higher than that of the norm ally grown sample in both forward and reverse bias. From temperature-d ependent analysis, the leakage current of the low-temperature sample i s contributed by the recombination current through defect levels aroun d the midgap, from which a recombination lifetime of 9.4X10(-12) a was obtained. By using admittance spectroscopy we observed a dominant ele ctron level at 0.60 eV with a corresponding capture cross section of 1 .0x10(-13) cm(2) that was not observed in the normally grown sample; t hus it is believed to be introduced by the As-rich low-temperature lay er. (C) 1997 American Institute of Physics.