Surface passivation of InGaAs/InP p-i-n Photodiodes using epitaxial regrowth of InP

The use of epitaxial regrowth of InP on lattice-matched In _0.53 Ga _0.47 As for passivation of photodiodes lateral mesa surfaces is investigated. The effect of the regrown layer was examined by photoluminescence and dark current measurements and compared with results obtained with SiO ₂ and Al ₂ O ₃ passivation layers. The integrated intensity of steady-state photoluminescence of InGaAs covered by InP increased by a factor between 15.5 and 58.9, depending on the excitation wavelength, denoting a strong reduction of nonradiative recombination. This reduction is expected to be the result of a strong reduction of intragap surface states. For the same photoluminescence measurements, both SiO ₂ and Al ₂ O ₃ oxide passivation instead showed a reduction of the photoluminescence intensity. The dark currents of p-i-n photodiodes showed less striking results, a fact that we claim, probably is related to residual doping of the InP regrown layer.