<title>InAsSb heterojunction photodiodes grown by liquid phase epitaxy</title>

Abstract

In this paper, the growth of p-n InAsSb/InSb heterojunction using liquid phase epitaxy (LPE) has been discussed. The layers have been grown on B InSb substrate using an In-rich solution in horizontal slider type boat. The active InAsSb layer was first grown with a desired composition. The carrier concentrations in the top layer in the range 10<SUP>16</SUP> cm<SUP>-3</SUP> to 10<SUP>20</SUP> cm<SUP>-3</SUP> was easily controlled using Cd doping. The standard structure consisted of 100 micrometers heavily doped n-type InSb substrate, an 10 micrometers InAsSb active region, and 2 micrometers heavily doped InSb p-type cap layer. Mirror like surface morphology was observed using a Nomarski differential interference contrast microscope. The structural characterization and the composition of InAsSb have been determined from x-ray diffraction data and IR transmission characteristic. The technology and construction of mesa photodiodes, both backside and frontside illuminated, have been presented. The analyses of the R<SUB>0</SUB>A product and current-voltage characteristics as a function of temperature shows that the dark currents of InSb/InSb photodiodes are diffusion limited. At higher As composition the R<SUB>0</SUB>A product is affected by the generation-recombination current of the depletion region.