Reliable operation of lattice-mismatched indium gallium arsenide photodetectors grown on silicon substrates

In/sub 0.53/Ga/sub 0.47/As-InP photodetectors for the 0.9-1.7 mu m spectrum have been fabricated with compositional step-grading (using hydride vapor phase epitaxy) upon both GaAs-Si substrates (deposited by metallorganic chemical vapor deposition) and bulk GaAs substrates. Both exhibited good device performance with dark currents (at -5 V) near 100 nA for the GaAs-Si substrate and near 1 nA for the bulk GaAs substrate. Measured dark currents decreased an order of magnitude sequentially as the applied stress was reduced from wafer form to chip form. Dark currents decreased further after 1500 h of aging at 125 degrees C.<
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