Influence of surface roughness on the electrical properties of Si-SiO{sub 2} interfaces and on second-harmonic generation at these interfaces
- 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-; ISSN 0734-211X; TRN: 95:004881-0052
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Vol. 11, Issue 4; Conference: 20. physics and chemistry of semiconductor interfaces, Williamsburg, VA (United States), 25-29 Jan 1993; Other Information: PBD: Jul-Aug 1993
- Country of Publication:
- United States
- Language:
- English
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