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Room Temperature Formation of Si-Nitride Films by LowEnergy Nitrogen Ion Implantation into Silicon
R. Hezel and N. Lieske l
Institut fiir Werksto~wissenschaften VI, Universitift Erlangen-N~rnberg, D-8520 Erlangen, Germany
ABSTRACTThe direct nitridation of silicon could be performed for the first time at room temperature by low energy nitrogen ion implantation up to the saturation concentration. Nearly stoichiometric Si-nitride layers with thicknesses from 1 to 9 nm were obtained for nitrogen ion energies in the range 500 eV-5 keV. The chemical composition and the electronic states as a function of depth were analyzed by a combination of Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS) with argon ion sputtering. Concentration depth profiles for different nitrogen ion energms and implantation times are presented.Thin films of amorphous Si-nitride play an important role as dielectric and passivation layers in microelectronic technology (1) and also appear to be very promising for photovoltaic solar cells (2). In the last Present address: Siemens AG, Data System Group, Munchen, Germany.Key words: Si-nitride films, ion implantation, de,pth profiling, Auger spectra, electron energy loss spectra.decade there has been growing interest in new low temperature production methods for Si-nitride layers and in the characterization of the microscopic properties (1).Preparation of homogeneous ultrathin Si-nitride layers with thicknesses below 10 nm is another very important problem, which in the case of silicon substrates could be solved by direct nitridation of silicon. This was done based on the chemical reaction of s...