Deep level defects in proton radiated GaAs grown on metamorphic SiGe/Si substrates

The effect of 2MeV proton radiation on the introduction of deep levels in GaAs grown on compositionally graded SiGe∕Si substrates was investigated using deep level transient spectroscopy (DLTS). Systematic comparisons were made with identical layers grown on both GaAs and Ge substrates to directly assess the influence of threading dislocations on radiation-related deep levels for both n-type and p-type GaAs. DLTS revealed that for p+n structures, proton irradiation generates electron traps at Ec−0.14eV, Ec−0.25eV, Ec−0.54eV, and Ec−0.72eV in the n‐GaAs base, and, for n+p structures, radiation-induced hole traps appear at Ev+0.18eV, Ev+0.23eV, Ev+0.27eV, and Ev+0.77eV in the p-type GaAs base, irrespective of substrate choice for both polarities. The primary influence of substituting SiGe∕Si substrates for conventional GaAs and Ge substrates is on the introduction rates of the individual traps as a function of proton radiation fluence. Substantially reduced concentrations are found for each radiation-induce...