Si-based materials and devices for light emission in silicon

We report on the fabrication and performances of extremely efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 mum electroluminescence (EL) at 300 K with a 10% external quantum efficiency, comparable to that of standard light-emitting diodes using III-V semiconductors. Er excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light-emitting MOS devices have been fabricated using Er-doped silicon rich oxide (SRO) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 1%. In these devices, Er pumping occurs by energy transfer from the Si nanostructures to the rare-earth ions. Finally, we have also fabricated MOS structures with Tb- and Yb-doped SiO2 which show room temperature EL at 540 nm (Tb) and 980 mn (Yb) with an external quantum efficiency of a 10% and 0.1%, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.