Implication of hydrogen-induced boron passivation in wet-chemically cleaned Si(111):H

Ristein J, Ley L (1997)


Publication Type: Journal article

Publication year: 1997

Journal

Publisher: Elsevier

Book Volume: 117/118

Pages Range: 32

Abstract

Atomically-flat, hydrogen-terminated Si(111) surfaces with a boron concentration range of 4.5 ∼ 11 × 1018 cm-3 have been prepared by a standard RCA cleaning step and subsequent 40% NH4F immersion followed by pure water dipping. The surface Fermi level for as-prepared Si(111) lies near midgap as confirmed by X-ray or ultraviolet excited photoelectron spectroscopy (XPS/UPS) and Kelvin probe measurements although occupied gap states density as low as 1011 cm-2 at most is verified from an extremely low photoelectron yield for photons with energies below ∼ 5 eV. Annealing at 360°C for 5 min causes the Fermi level to shift towards the valence-band maximum top by ∼ 0.2 eV without an appreciable increase in the gap state density and a change in hydrogen surface termination. These observations imply a hydrogen-induced passivation of boron atoms in a surface layer during wet-chemical cleaning and the reactivation of such passivated boron atoms by 360°C annealing. For annealing temperatures above 460°C, hydrogen desorption from the surface results in a true pinning of the Fermi level close to midgap because of the generation of surface gap states.

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How to cite

APA:

Ristein, J., & Ley, L. (1997). Implication of hydrogen-induced boron passivation in wet-chemically cleaned Si(111):H. Applied Surface Science, 117/118, 32.

MLA:

Ristein, Jürgen, and Lothar Ley. "Implication of hydrogen-induced boron passivation in wet-chemically cleaned Si(111):H." Applied Surface Science 117/118 (1997): 32.

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