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1

Adsorption of Oxygen on HF-Etched Si(111) Surfaces: XPS Study

100%

Iwanowski R. J., Sobczak J. W.

Acta Physica Polonica A

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1997

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vol. 91

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issue 4

793-796

EN

X-ray photoelectron spectroscopy studies of the Si(111) surfaces, after dilute HF etching and methanol rinse, are reported. These included a detailed analysis of the main core-levels (Si 2p, O 1s) and the valence band spectra. The observed asymmetry of the O 1s lines was attributed to two contributing subpeaks: the main (1) and the minor one (2), shifted ≈ 1.5 eV to higher binding energies. Their relative intensity was found to depend on the air exposure time and on the take-off angle. The peaks were assigned to two different positions of surface oxygen: (1) O chemisorbed with methoxy group, (2) bridging O atom. The valence band X-ray photoelectron spectroscopy spectra reveal the influence of surface states induced by the "chemisorbed O"-Si bond.

2

X-Ray Photoelectron Study of Yb-Doped InP

81%

Iwanowski R. J., Sobczak J. W., Kaliński Z.

Acta Physica Polonica A

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1997

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vol. 91

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issue 4

809-813

EN

X-ray photoelectron spectra of core levels are reported for InP:Yb. Crystalline InP, doped with Yb to a level of 0.5 at.%, was grown by the synthesized solute diffusion method. An analysis of the core-level spectra of the constituent components, i.e. In 3d_{5/2} and P 2p, revealed a minor influence of the surface oxide species, mainly in the phosphate-like form. The spectrum of the Yb 4d core level was also recorded. The energy of the Yb 4d_{3/2} peak was found identical to that in Yb metal, whereas the 4d_{5/2} peak was found to be shifted to higher binding energies. This effect was found comparable to the case of advanced oxidation of Yb thus confirming its high reactivity, even as a bulk dopant. The data give also a rare experimental example of detection of bulk dopant atoms in a semiconductor matrix by X-ray photoelectron spectroscopy at the limit of detectability.

3

X-Ray Photoelectron Spectroscopy and Optical Reflectivity Studies of Si Surfaces Prepared by Chemical Etching

81%

Iwanowski R. J., Sobczak J. W., Kowalski B. J.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

825-830

EN

Complementary X-ray photoelectron spectroscopy and optical reflectivity studies of crystalline Si(111) surfaces prepared by two different wet chemical etching processes were performed. These included aqueous HF solution etch or diluted CP-4 bath. Optical reflectivity spectra of Si surfaces, measured in the range 3.7-11 eV, were found strongly dependent on the applied etching process. Analysis of the core level X-ray photoelectron spectroscopy data has shown similarity of the surface structure, irrespectively of the etching procedure. Finally, comparison of optical reflectivity and valence band X-ray photoelectron spectra revealed a qualitative correlation between them indicating dominant influence of the bulk (here, the subsurface region containing polishing-induced defects) in the case studied. This paper is the first one which presents correlations between optical reflectivity and X-ray photoelectron spectroscopy data for Si and thus illustrates a bulk sensitivity of both techniques considered.

4

Photoemission and Inverse Photoemission Studies of SiO_{2}

81%

Sobczak A., Nietubyć R., Sobczak J. W.

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EN

Occupied and unoccupied electron states of amorphous silicon dioxide film supported on Si crystal are studied by using X-ray photoemission and, for the first time, X-ray inverse photoemission (X-ray bremsstrahlung isochromat method). A special care was undertaken to minimize decomposition of silicon oxide during X-ray bremsstrahlung measurements. The experimental spectra are compared with theoretical band structure calculations for amorphous SiO_{2} from the literature and good overall agreement is found.

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4 Acta Physica Polonica A

2 1997

2 1994

4 Sobczak J. W.

3 Iwanowski R. J.

1 Kaliński Z.

1 Kowalski B. J.

1 Nietubyć R.

1 Sobczak A.

Adsorption of Oxygen on HF-Etched Si(111) Surfaces: XPS Study

X-Ray Photoelectron Study of Yb-Doped InP

X-Ray Photoelectron Spectroscopy and Optical Reflectivity Studies of Si Surfaces Prepared by Chemical Etching

Photoemission and Inverse Photoemission Studies of SiO_{2}