Broad-spectrum light emission at microscopic breakdown sites in metal-insulator-silicon tunnel diodes

Abstract

In addition to Si band-edge electroluminescence (EL) near 1.1 eV, we observe hot-electron EL in metal-insulator-silicon tunnel diodes that can span a detector-limited range from 0.7 to 2.6 eV (1780-480 nm). The maximum photon energy increases with increasing forward bias. In one implementation, sub-micron-sized EL sites appear during the forward-bias stress. The number of sites grows linearly with the current, consistent with the dielectric breakdown of the insulator. We compare the poststress current-voltage data with the quantum-point-contact model. Results are presented for various p-type Si(100) devices having 2-8-nm-thick SiO2, Al2O3, and HfOxNy insulators. We also describe devices in which electron-beam lithography of an 18-nm-thick SiO2 is used to define EL sites. (c) 2005 American Institute of Physics.