S. D. Kosowsky

X-ray grazing incidence diffraction from alkylsiloxane monolayers on silicon wafers

X‐ray reflection (both specular and off‐specular) and grazing incidence diffraction (GID) have been used to study the structure of alkylsiloxane monolayers (n‐C18H37SiO1.5) formed by self‐assembly from solution on silicon wafers. GID studies of complete monolayers reveal a single ring of scattering associated with the monolayer. The Lorentzian line shape of this ring indicates that the film is characterized by liquidlike order, with a typical translational correlation length of about 45 A. The thermal coefficient of expansion of the monolayer, as determined from the GID peak position, is approximately equal to the value for liquid n‐alkanes. Upon either heating or cooling, the monolayer correlation lengths decrease, suggesting that the differential thermal‐expansion coefficients of the film and substrate figure prominently in thermal changes of the molecular ordering. GID data for incomplete monolayers also reveal a single ring of scattering associated with the monolayer. While both the translational corr...

Evidence of Annealing Effects on a High-Density Si/SiO2 Interfacial Layer

Thermally grown Si(001)/SiO2 samples were studied by x-ray reflectivity. Fits of model electron density profiles to the data reveal the existence of an interfacial layer at the Si/SiO2 interface up to 15-A-thick, with density higher than either the crystalline Si or the main oxide layer. This density of the layer is reduced by a postoxidation anneal.

An X-ray scattering study of SiOx/Si/Ge(001)

Abstract X-ray scattering has been used to study the interfacial structure of a dry oxide grown at room temperature on a system consisting of four layers of Si epitaxially grown on Ge(001). The model producing the best fit to the data consists of a Ge single-crystal substrate, five intermediate ordered layers and an amorphous oxide layer. Unlike the dry oxide grown on an atomically flat Si(001) substrate which consists of a 5 A layer of amorphous SiO 2 with some laminar order in the growth direction [1], the observed amorphous oxide layer is about 8–9 A thick and lacks appreciable laminar order. Together with X-ray Photoelectron Spectroscopy (XPS) data, the data indicate that not all of Si is oxidized and that there exists oxidized Ge in the amorphous layer.