High-Speed and High-Sensitivity Metal-Semiconductor-Metal Photodetectors for Optoelectronic Integrated Circuit Applications

139 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.A variety of techniques to enhance the sensitivity and bandwidth of front-illuminated MSMPDs is presented, proposed, and demonstrated. A reduction in the absorption layer thickness of a conventional InGaAs-based MSMPD enabled bandwidths in excess of 19 GHz, at a wavelength of 1.55 $\mu$m, to be obtained with the use of simple optical lithography tools. MSMPDs using an InGaAs absorption layer, employing a conventional layout, and utilizing transparent electrode materials composed of combinations of $\rm In\sb2O\sb3,$ CdO, and SnO$\sb2$ achieved responsivities of up to 0.69 A/W at a wavelength of 1.3 $\mu$m. Modifications to the layout of the conventional MSMPD enabled enormous reductions in dark current to be obtained. These modifications afford a reduction in dark current by reducing thermionic emission processes at the Schottky contacts of the MSMPDs. An MSMPD exhibiting 52.9 pA of dark current corresponding to a dark current density of 21.1 fA/$\rm\mu m\sp2$ was demonstrated.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD