New metastable defects in GaAs

摘要

Two previously unreported metastable defects innhyphen;type GaAs epitaxial layers grown by metalorganic chemical vapor deposition have been identified by deep level transient spectroscopy. These levels, here labeledM3 andM4, have activation energies for thermal emission of electrons of 0.31 and 0.61 eV, respectively. Formation of theM4 center and annealing of theM3 center are observed to take place when a reverse bias is applied to Schottky diodes at elevated temperatures. The reverse transition is observed under zero bias at elevated temperatures (e.g., 400 K). An additional metastable defect, labeledM2, with transformation properties similar to those of theM4 center and an emission activation energy of 0.64 eV, was observed in samples which received a rapid thermal anneal at temperatures of 900thinsp;deg;C and above.