Deep levels in p-type InGaAsN lattice matched to GaAs

Deep-level transient spectroscopy measurements were utilized to investigate deep-level defects in metal-organic chemical vapor deposition-grown, unint entionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the band gap, with a dominant hole trap at E-v +0.10 eV. Postgrowth anneali ng simplified the deep-level spectra, enabling the identification of three distinct hole traps at 0.10, 0.23, and 0.48 eV above the valence-band edge, with concentrations of 3.5X10(14), 3.8X10(14), and 8.2X10(14) cm(-3), resp ectively. A direct comparison between the as-grown and annealed spectra rev ealed the presence of an additional midgap hole trap, with a concentration of 4X10(14) cm(-3) in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material q uality and minority-carrier properties after annealing. Of the four hole tr aps detected, only the 0.48 eV level is not influenced by annealing, sugges ting this level may be important for processed InGaAsN devices in the futur e. (C) 1999 American Institute of Physics. [S0003-6951(99)05119-0].