Influence of surface roughness on the electrical properties of Si-SiO{sub 2} interfaces and on second-harmonic generation at these interfaces

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena

DOI:https://doi.org/10.1116/1.586963· OSTI ID:161732

Bjorkman, C H; Yasuda, T; Shearon, Jr, C E ^[1]

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1. North Carolina State Univ., Raleigh, NC (United States); and others

Si(111) wafers, cut at angles between 0{degrees} and 5{degrees} in the [11{bar 2}] direction, were prepared by a standard RCA cleaning process followed by a rinse in HF/NH{sub 4}F solutions with different pH values. Si-SiO{sub 2} structures were formed on these surfaces by a two-step low-temperature plasma-assisted oxidation/deposition process, and compared with interfaces formed by thermal oxidation, followed by rapid thermal annealing. The Si(111)-SiO{sub 2} interface, subjected to predeposition rinse in a 40 wt.% NH{sub 4}F solution, displayed a midgap interface trap density D{sub it}, of {approximately}4 X 10{sup 10} cm{sup -2} eV{sup -1}. The D{sub it} values increased systematically up to {approximately}2 X 10{sup 11} cm{sup -2} eV{sup -1} as the pH of the final rinse was decreased. Using a second-harmonic generation pumped at 1053 nm, the influence of off-axis orientation and surface structure of Si(111) surfaces was examined. The surface structure was modified by thermal oxidation at 850{degrees}C, annealing at temperatures in the range of 900-1100{degrees}C, and removing the oxide in a HF solution. Changes in the characteristic rotational anisotropy are analyzed using harmonic functions reflecting the onefold and threefold symmetry of vicinal Si(111) surfaces, and are compared with changes in the thermal oxide D{sub it} values on annealing. 23 refs., 7 figs., 1 tab.

• OSTI ID: 161732
• Report Number(s): CONF-930115--
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 4 Vol. 11; ISSN JVTBD9; ISSN 0734-211X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
ANNEALING
CORRELATIONS
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
HARMONIC GENERATION
INTERFACES
NONLINEAR OPTICS
OXIDATION
PLASMA
ROUGHNESS
SILICA
SILICON
SURFACES
TRAPS