A morphology study of the thermal oxidation of rough silicon surfaces

Abstract

Effects of atomic-scale surface morphology on carbon nanotube alignment on thermally oxidized silicon surface Appl. Phys. Lett. 96, 103102 (2010); 10.1063/1.3354009 Effect of surface roughness on thermal conductivity of silicon nanowiresA report on the thermal oxidation of rough silicon surfaces as measured by spectroscopic immersion ellipsometry and atomic force microscopy ͑AFM͒ is given. It was found that, as the thickness of the thermally grown SiO 2 overlayer increases, the average radius of the crystalline silicon protrusions ͑roughness͒ at the interface decreases. A fractal analysis shows that a simpler surface results from oxidation. The frequency spectra of AFM images are concordant with the fractal analysis and shows that small features oxidize faster. This is in agreement with the predictions of the Kelvin equation that small features are more reactive.

Limiting Si/SiO2 interface roughness resulting from thermal oxidation

“…Thus, there is reduced tolerance for interfacial defects, such as interface roughness, since such roughness causes carrier scattering and electric-field enhancement effects, which can result in hindered carrier mobility, 1,2 leakage current, and dielectric breakdown. 3,4 It has been shown that both thermal 5,6 and microwave electron cyclotron resonance ͑ECR͒ plasma 6 oxidation processes smoothen initially rough Si surfaces via a free-energy reduction mechanism according to the Kelvin equation for purely thermal oxidation, and in addition to local electricfield enhancement effects for ECR oxidation. It has also been shown 6 that these oxidation processes roughen initially smooth Si surfaces but with the underlying reason uncertain.…”

“…Two roughness parameters are used together, root-mean-square roughness ͑rms͒ and fractal dimension (D F ), which have been shown to provide a reasonably complete surface roughness description. 5,11,12 Spectroscopic ellipsometry ͑SE͒ is also utilized for roughness of the thermally annealed samples which have a negligible SiO 2 overlayer.…”

Roughness models for particle adhesion

“…Fractals have been employed to characterize surface roughness in much the same way as has the value of the root mean square (RMS) roughness. A number of papers have discussed determining fractal parameters for use in comparing the roughness of two surfaces [27][28][29][30][31]. With the exception of the fractal dimension, D, and the fractal roughness, G, other parameters in Eq.…”

Area evaluation of microscopically rough surfaces

“…Previous studies [1][2][3] have shown that by using two roughness parameters, root-mean-square ͑rms͒ roughness and fractal dimension (D F ), a reasonably complete description of surface roughness is achieved. rms contains vertical roughness information, while D F provides spatial information.…”