Si (100)– SiO 2 interface properties following rapid thermal processing

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Abstract
An experimental examination of the properties of the Si(100)–SiO 2 interface measured following rapid thermal processing(RTP) is presented. The interfaceproperties have been examined using high frequency and quasi-static capacitance-voltage (CV) analysis of metal-oxide-silicon (MOS) capacitor structures immediately following either rapid thermal oxidation (RTO) or rapid thermal annealing (RTA). The experimental results reveal a characteristic peak in the CV response measured following dry RTO and RTA (T>800 ° C ), as the Fermi level at the Si(100)–SiO 2 interface approaches the conduction band edge. Analysis of the QSCV responses reveals a high interface state density across the energy gap following dry RTO and RTA processing, with a characteristic peak density in the range 5.5×10 12 to 1.7×10 13 cm −2 eV −1 located at approximately 0.85–0.88 eV above the valence band edge. When the background density of states for a hydrogen-passivated interface is subtracted, another peak of lower density (3×10 12 to 7×10 12 cm −2 eV −1 ) is observed at approximately 0.25–0.33 eV above the valence band edge. The experimental results point to a common interface state defect present after processes involving rapid cooling (10 1 –10 2 ° C/s ) from a temperature of 800 °C or above, in a hydrogen free ambient. This work demonstrates that the interface states measured following RTP (T>800 ° C ) are the net contribution of the P b0 /P b1 silicondangling bond defects for the oxidized Si(100) orientation. An important conclusion arising from this work is that the primary effect of an RTA in nitrogen (600–1050 °C) is to cause hydrogen desorption from pre-existing P b0 /P b1 silicondangling bond defects. The implications of this work to the study of the Si–SiO 2 interface, and the technological implications for silicon based MOS processes, are briefly discussed. The significance of these new results to thin oxide growth and optimization by RTO are also considered.