Chemical and Electrical Passivation of Single-Crystal Silicon(100) Surfaces Through a Two-Step Chlorination/Alkylation Process

Journal Article · Sun Jan 01 04:00:00 EST 2006 · J. Phys. Chem. B

DOI:https://doi.org/10.1021/jp056773x· OSTI ID:913952

Nemanick, E; Hurley, P; Webb, L; Knapp, D; Michalak, D; Brunschwig, B; Lewis, N

Single-crystal Si(100) surfaces have been functionalized by using a two-step radical chlorination-Grignard (R= MgCl, R = CH{sub 3}, C{sub 2}H{sub 5}, C{sub 4}H{sub 9}, C{sub 6}H{sub 5}, or CH{sub 2}C{sub 6}H{sub 5}) alkylation method. After alkylation, no chlorine was detectable on the surface by X-ray photoelectron spectroscopy (XPS), and the C 1s region showed a silicon-induced peak shift indicative of a Si-C bond. The relative intensity of this peak decreased, as expected, as the steric bulk of the alkyl increased. Despite the lack of full alkyl termination of the atop sites of the Si(100) surface, functionalization significantly reduced the rate of surface oxidation in air compared to that of the H-terminated Si(100) surface, with alkylated surfaces forming less than half a monolayer of oxide after over one month of exposure to air. Studies of the charge-carrier lifetime with rf photoconductivity decay methods indicated a surface recombination velocity of <30 cm s{sup -1} for methylated surfaces, and <60 cm s-1 for Si surfaces functionalized with the other alkyl groups evaluated. Soft X-ray photoelectron spectroscopic data indicated that the H-Si(100) surfaces were terminated by SiH, SiH{sub 2}, and SiH{sub 3} species, whereas Cl-Si(100) surfaces were predominantly terminated by monochloro (SiCl and SiHCl) and dichloro (SiCl{sub 2} and SiHCl{sub 2}) Si species. Methylation produced signals consistent with termination by Si-alkyl bonding arising from SiH(CH{sub 3})-, SiH{sub 2}(CH{sub 3})-, and Si(CH{sub 3}){sub 2}-type species.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 913952
• Report Number(s): BNL--78520-2007-JA
• Journal Information: J. Phys. Chem. B, Journal Name: J. Phys. Chem. B Vol. 110; ISSN 1089-5647; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
43 PARTICLE ACCELERATORS
ALKYLATION
CHLORINATION
MONOCRYSTALS
NSLS
PASSIVATION
SILICON
X-RAY PHOTOELECTRON SPECTROSCOPY
national synchrotron light source