Nitrogen Adsorption of Si(100) Surface by Plasma Excited Ammonia

P. Pungboon PANSILA
Shigeru KUBOTA
Fumihiko HIROSE

IEICE TRANSACTIONS on Electronics   Vol.E98-C    No.5    pp.395-401
Publication Date: 2015/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E98.C.395
Type of Manuscript: Special Section PAPER (Special Section on Fundamentals and Applications of Advanced Semiconductor Devices)
Plasma,  plasma excited NH3,  IR absorption spectroscopy,  XPS,  

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Nitrogen adsorption on thermally cleaned Si(100) surfaces by pure and plasma excited NH3 is investigated by in situ IR absorption spectroscopy and ex-situ X-ray photoelectron spectroscopy with various temperatures from RT (25°C) to 800°C and with a treatment time of 5 min. The nitrogen coverage after the treatment varies according to the treatment temperature for both pure and plasma excited NH3. In case of the pure NH3, the nitrogen coverage is saturated as low as 0.13–0.25 mono layer (ML) while the growth of the nitride film commenced at 550°C. For the plasma excited NH3, the saturation coverage was measured at 0.54 ML at RT and it remained unincreased from RT to 550°C. This indicates that the plasma excited NH3 enhances the nitrogen adsorption near at RT. It is found that main species of N is Si2= NH in case of the plasma excited NH3 at RT while the pure NH3 treatment gives rise to the Si–NH2 passivation with Si–H at RT. We discuss the mechanism of the nitrogen adsorption on Si(100) surfaces with the plasma excited NH3 in comparison with the study on the pure NH3 treatment.