ATOMISTIC CHARACTERIZATION OF RADICAL NITRIDATION PROCESS ON Si(100) SURFACES

摘要

Initial nitridation process on clean Si(100)-2x1 surfaces has been investigated by scanning tunneling microscopy and scanning tunneling spectroscopy. Radical nitrogen was used as a nitridation source. Changes of Si surface structures and electronic states during the nitridation were characterized on an atomic scale. It is found that both die nitridation and the detachment of the surface Si atoms occur simultaneously at a very initial stage. These phenomena induce the formation of characteristic surface defects, step structures, and nitride islands whose morphologies critically depend on the substrate temperature. Conformable silicon nitride films can be obtained at 500°C and metal-insulator-semiconductor capacitors made from the films exhibit electrical properties of low hysteresis and low leakage current density, which meet criteria for gate insulators in advanced transistors.