Accumulation of hydrogen near the interface between ultrathin SiO2 and Si(001) under ion irradiation in high-resolution elastic recoil detection

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 249; no. 1-2; pp. 425 - 428
• Main Authors: Nakajima, Kaoru, Imaizumi, Ryo, Suzuki, Motofumi, Kimura, Kenji
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2006
• Subjects: Elastic recoil detection (ERD); Hydrogen; Irradiation effect; SiO2; 79.20.Rf; Elastic recoil detection (ERD); Hydrogen; 61.80.Jh; Irradiation effect; SiO2; 82.80.Yc
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2006.04.044

Depth profiles of hydrogen in a ultrathin (2.1nm) SiO2 film grown on Si(001) have been measured using high-resolution elastic recoil detection (ERD) to investigate redistribution of hydrogen atoms by ion-beam irradiation in ERD itself. During irradiation of 400keV C+, steep decrease of hydrogen density at the surface and gradual increase of hydrogen density near the SiO2/Si interface was observed. A model that involves irradiation-induced desorption of hydrogen atoms from the surface and re-adsorption of residual gas molecules containing hydrogen atoms on the surface successfully explains the decrease of hydrogen density at the surface. The increasing hydrogen atoms near the SiO2/Si interface originate in the adsorbed hydrogen on the surface, suggesting that hydrogen atoms recoiled inward from the surface accumulate near the SiO2/Si interface. According to this “recoil” model, the recoil cross section for hydrogen by 400keV C+ is estimated to be 7×10−17cm2.