J-V characteristics for InGaP diodes grown on SiGe/Si and GaAs substrates obtained at 300 K. The reverse bias leakage current was below the detection limit of 0.1 nA/cm2 for both cases out to ∼−2V reverse bias.
(a) DLTS spectra obtained for identical n+p InGaP diodes grown on SiGe/Si and GaAs substrates. The data shown corresponds to a measurement rate window of 0.8 s−1. (b) DLTS data for a wide range of rate windows is shown in the usual Arrhenius format from which the activation energy and capture cross section are derived. These values are listed in Table I.
Steady state photocapacitance spectra obtained at 300 K for p-InGaP grown on SiGe/Si and GaAs substrates. Three deep levels with photocapacitance onset energies at Ev + 1.18 eV, Ev + 1.36 eV, and Ev + 1.78 eV are observed for both sample types. The band edge is also identified as shown in the figure.
(a) Derivative of the photocapacitance at different time intervals for InGaP/SiGe indicating energy ionization onsets at Ev + 1.18 eV and Ev + 1.36 eV. (b) Optical cross section spectra for p-InGaP grown on SiGe/Si for t = 0–0.3 s. Onsets at EV + 1.36 eV and EV + 1.79 eV are observed. Similar onsets are found for InGaP/GaAs.
Qualitative diagram of the deep level distribution within p-type InGaP/SiGe/Si and InGaP/GaAs bandgap representing the quantitative concentration of the levels within the bandgap. An overall higher trap concentration is observed for the sample grown on the metamorphic SiGe/Si substrate.
Trap parameters obtained from DLTS and DLOS measurements for bandgap states detected in p-type InGaP layers grown on both SiGe/Si and GaAs substrates.
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