Investigation of strain effects on performance of high-speed Schottky-type photodetectors

PIN and Schottky photodetectors (PDs) having an InGaAs absorption layer are widely used for long distance optical communication. The speed of those PDs is generally limited by hole transition time in the absorption layer. This limit can be overcome by using a tensile-strain In/sub x/Ga/sub 1-x/As (x<0.53) absorption layer. We fabricated and characterized Schottky-type PDs having a lattice-matched In/sub 0.53/Ga/sub 0.47/As absorption layer and a tensile-strained In/sub 0.48/Ga/sub 0.52/As absorption layer. Photocurrent impulse response of the tensile-strained InAlAs/In/sub 0.48/Ga/sub 0.52/As PD showed an improved FWHM of 13 ps, while that of the the lattice-matched InAlAs/In/sub 0.53/Ga/sub 0.47/As PD was 16 ps.