ELECTRICAL AND OPTICAL-PROPERTIES OF OXYGEN-ION HOT-IMPLANTED GAAS-LAYERS

Oxygen-ion hot implantation into undoped GaAs has been investigated as fundamental research for the purpose of fabricating highly resistive isolation regions at lower temperatures. Hot implantation at 300-degrees-C at an energy of 170 keV and a dose of 1 X 10(15) cm-2 results in a sheet resistivity of 4 X 10(6) OMEGA/square without post-implant annealing and 7.7 X 10(6) OMEGA/square after annealing at 400-degrees-C for 10 min. These values are about one order of magnitude higher than those obtained after implantation at the same energy and dose done at room temperature. This high resistivity of the hot-implanted layers is caused by both the removal of hopping conduction with an activation energy of 0.06 eV and the formation of 0.24-0.27 eV deep-level electron traps. The effective reduction in implantation damage resulting from hot implantation, which induces the removal of hopping conduction, is confirmed by laser Raman spectroscopy.