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Rare-Earth Doping in SiC for Light-Emitting Devices

Neodymium-doped SiC thin films are grown by means of supersonic free jets which are introduced into the vacuum chamber using a pulsed supersonic valve. Metal-organic complexes of Nd are mixed with a SiC film precursor, tetramethylsilane Si(CH3)4, to generate a molecular beam. Films were grown on p-type Si(100) substrates at 900° C from the molecular free jets for 90 min with different electron beam energies ranging from 25 to 75 eV. Cross-sectional transmission electron microscope images and diffraction patterns have shown that these SiC films were epitaxially grown zincblende or β-SiC (3C-SiC). Secondary ion mass spectrometry measurements of several doped SiC samples have revealed the depth profiles and doping concentrations of Nd ranging up to 5.8×1019 cm-3 depending on the electron beam energy. However, no appreciable photoluminescence corresponding to the Nd3+ ion was detected suggesting that neodymium is not incorporated as an optically active trivalent ion.