| Popis: |
The anodic behavior of Si in dilute NH 3 solutions has been investigated with the aim of producing thin gate oxides of thickness between 4 and 15 nm. The oxide is formed under potentiostatic conditions and in varying solution concentrations. The thickness is calculated from x-ray photoelectron spectroscopy (XPS) which has been calibrated with nuclear reaction analysis, using the 16 O(d,p) 17 O reaction. The anodic growth process yields very clean oxide, contaminated only with adventitious carbon on the surface as well as ≤1 at. percent nitrogen within the bulk (as detected by XPS). The nitrogen impurity is present in various oxidation states depending on the formation conditions. Its concentration can be decreased by annealing the samples, decreasing the concentration of NHs in solution, or by cathodic reduction |
Plný text