High-resolution X-ray diffraction of silicon-on-nothing

Abstract

High-resolution multi-crystal X-ray diffraction was employed to characterize silicon-on-nothing samples consisting of a one-dimensional periodic array of buried empty channels. p-and n-type silicon starting wafers were used for sample preparation. For the p-type samples, this periodic array gives rise to well defined Fraunhofer diffraction when the channels are normal to the scattering plane. This indicates good lattice quality of the layer containing the channels. Moreover, the lattices of the surface layer and the layer with the channels were almost indistinguishable from that of perfect silicon. Conversely, the n-type samples showed such lattice tilts and out-of-plane mosaic spreads in the surface and buried layers that Fraunhofer diffraction does not occur from the periodic array of the channels. The elucidation of this different behaviour is in progress and will most likely be fruitful after X-ray images of the same samples are taken.

Determination by high-resolution X-ray diffraction of shape, size and lateral separation of buried empty channels in silicon-on-nothing architectures

“…In this paper, which follows the previous publication on the first results obtained on SON by high-resolution X-ray diffraction (Servidori & Ottaviani, 2005), a further step forward of the structural investigation is reported. In fact, by using the same experimental high-resolution laboratory X-ray apparatus, the period, shape and size of the buried channels were determined along with the Si lateral gap between them.…”

“…[001] CZ Si wafers of p-type (boron-doped, 12-18 cm) from MEMC Electronic Materials were used as starting substrates for sample preparation. A few details of the sample processing steps are described elsewhere (Servidori & Ottaviani, 2005). Here we show only how the cross sections of the wafers look at the beginning and the end of the SON process ( Fig.…”

“…A multi-crystal X-ray diffractometer with Cu K radiation from a 12 kW rotating-anode source was used for the measurements. Details of the experimental apparatus are given by Servidori & Ottaviani (2005). We only recall here that the sample, oriented according to the symmetric 004 reflection, receives a beam from a two 004 asymmetric reflection Si collimator having parallel divergences (in the diffraction plane) of 0.59 and 0.21 arc s for and polarizations, respectively.…”