Erbium-doped silicon films grown by plasma-enhanced chemical-vapor deposition

Abstract

Epitaxial growth of erbium-doped silicon films has been performed by plasma-enhanced chemical vapor deposition using an electron-cyclotron-resonance source. The goal was to incorporate erbium as an optically active center (ErO6) through the use of metal-organic dopant sources. The characteristic 1.5 μm emission was observed by photoluminescence. Chemical analysis of the film revealed, however, that the organic ligands were decomposing and contributing to the carbon contamination of the films. Analysis of the molecular flux to the substrate indicated that the metal-organic compound used, tris(2,2,6,6-tetramethyl-3-5-heptanedionato)erbium(III), was most likely to decompose, and supply unbonded atomic erbium and not the optical active species, ErO6. Excessive carbon contamination lowered epitaxial quality and reduced the photoluminescent intensity. Photoluminescent intensity was improved by a 600 °C anneal but was strongly quenched by a 900 °C anneal. The low-temperature anneal improved crystal quality, and the high-temperature anneal resulted in silicide formation.