Dark current reduction for 2.5 /spl mu/m wavelength, 2% mismatched InGaAs photodetectors, by changing bufferlayer structure and growth temperature

We describe the influence of growth temperature, buffer layer structure and substrate orientation on the dark current density of test devices. All growth runs were performed by means of low-pressure MOVPE, using a horizontal liner. The processing of these devices consisted of deposition of TiAu contacts, by using a removable Ni mask, with openings of different size and shape. These metal contacts were in turn used as a mask for the etching of the mesa.