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Ultraviolet photoelectron spectroscopy (UPS) studies of initial stages of copper deposition from bis(hexafluoroacetylacetonato)copper(II) (Cu(hfac)2) on Si(111)-7x7 at room temperature. Part A

C. IONESCU1,* , M. A. IONESCU1, I. CIUCA1

Affiliation

  1. Faculty of Science and Materials Engineering, Politechnical University of Bucharest, Romania, UE

Abstract

Organometallic chemical vapour depostion (OMCVD) of copper compounds is the preferred method for metallization of semiconductors over physical vapour deposition. The advantages of CVD are selectivity and ambient conditions for deposition (low vacuum and room temperature). UPS spectra of Cu deposited from Cu(hfac)2 via chemical vapour deposition onto Si(111)-7x7 were studied for apparent exposures of 0.02, 0.04, 0.06, 0.08, 0.1 L at room temperature. The UPS spectra after each deposition showed a difference in the valence features for the Si in the range -2.5 to -15 eV, suggesting that a transformation occurred from one deposition to another. The reduction in the peak intensity for Si(111)- 7x7 bulk states (-4 eV and -8 eV) as the deposition proceeds (exposures of 0.04 and 0.06 L), is accompanied by a concomitant increase in the secondary electron peak (~ -17 eV) for the same exposures, suggesting that the sample is receiving an increased amount of Cu (I) and fluorinated moities. Data are similar to those obtained by Tadayyon 11 for organics. The difference in the intensity of the spectra between 0.08 L and 0.1 L suggested that the local density of states around Si is affected by a continuous increase in the number of Cu atoms with the exposure..

Keywords

Chemical vapour deposition, Copper, Low index single crystal Si surfaces, Ultraviolet photoelectron spectroscopy.

Citation

C. IONESCU, M. A. IONESCU, I. CIUCA, Ultraviolet photoelectron spectroscopy (UPS) studies of initial stages of copper deposition from bis(hexafluoroacetylacetonato)copper(II) (Cu(hfac)2) on Si(111)-7x7 at room temperature. Part A, Optoelectronics and Advanced Materials - Rapid Communications, 5, 7, July 2011, pp.722-725 (2011).

Submitted at: June 22, 2011

Accepted at: July 25, 2011