Light-emitting diodes fabricated in silicon/iron disilicide

Attempts to obtain electroluminescence from silicon-based devices have been largely frustrated by the indirect bandgap of the semiconductor. One approach, described here, is to fabricate a direct bandgap material which is compatible with silicon processing and which can then be excited via standard carrier injection across p-n junctions. We have used ion implantation of iron, typically at an energy of 180 keV and a dose of 1.5 x 10(16) cm(-2), conditions which are easily achievable in modem commercial implanters; to form precipitates of beta-iron disilicide, which has a direct bandgap of 0.8 eV. At 80 K and under forward bias conditions, the devices emit light at 1.5 mu m with an. external quantum efficiency of 5 x 10(-3), and emission at room temperature. has been observed The emission lifetime has been placed at shorter than 60 ns, as expected of a direct bandgap material. Results will be presented showing how the electroluminescence properties change with the dose of implanted iron.