X-ray emission spectra and the effect of oxidation on the local structure of porous and spark-processed silicon

Abstract

The paper presents a comparison of x-ray emission spectra of porous silicon (P-Si) and of spark-processed silicon (sp-Si). Both types of Si structure display strong photoluminescence in the visible range of the spectrum. Porous samples were prepared by anodization of and Si wafers. Whereas for the P-Si processed from Si the presence of some amorphous silicon is detected, the x-ray emission spectra of porous Si prepared from Si display a higher content of . For spark-processed Si the x-ray emission spectra reveal a much stronger degree of oxidation which extends to depths larger than 10 000 Å. Furthermore, the chemical state of silicon atoms of sp-Si measured at the centre of the processed area is close to that of silicon dioxide, and depends slightly on the emission maximum. Specifically, green-photoluminescing sp-Si shows a higher degree of oxidation than the blue-luminescing specimen. However, the depth of oxidation consistently decreases for areas with weak photoluminescence and without photoluminescence. Possible origins for the photoluminescence are discussed.

The influence of high-energy electron irradiation and boron implantation on the oxide thickness in the /Si system

“…In comparison with the results obtained for the first series, we have found in this case a high resistance of the p-Si substrate to oxidation induced by high-energy electron radiation under the same conditions. This conclusion is in agreement with our previous measurements of the Si L 2,3 XES of porous silicon [16]. According to those measurements, porous silicon prepared by anodizing p-Si is more stable against oxidation than that prepared by anodizing n-Si.…”

“…Measurements of the surface density of oxygen atoms were made by the nuclear reaction technique on a 2 MV Van de Graaf accelerator. To measure the surface oxygen atom density, two reactions, 16 O(d, p 1 ) 17 O and 16 O(d, p 0 ) 17 O, can be used. Since the 16 O(d, p 0 ) 17 O reaction has a small cross-section, the nuclear reaction 16 O(d, p 1 ) 17 O was used here.…”

“…To measure the surface oxygen atom density, two reactions, 16 O(d, p 1 ) 17 O and 16 O(d, p 0 ) 17 O, can be used. Since the 16 O(d, p 0 ) 17 O reaction has a small cross-section, the nuclear reaction 16 O(d, p 1 ) 17 O was used here. The energy of the primary deuteron beam and the irradiation dose were 900 keV and 160 µC, respectively.…”

Soft X‐ray emission electron microscopy: chemical state microscopy from interface and bulk

“…The tantalum covered substrate shows a silicon L fluorescence spectrum with a clear fingerprint of the silicon oxide. [11] The sharp peak at 88 eV is a second order contribution from Ta 4d 5/2 -4p 3/2 fluorescence; weak features around 97 eV can also be attributed to Ta 5p-4d transition in second order of the spectrometer. On the letter the fluorescence spectrum is strongly attenuated due to the cobalt layer.…”