AVS 46th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM1-ThA

Paper EM1-ThA9
Chlorosilane Treatment of SiO@sub 2@-Covered Si Surfaces for Modification of their Chemical Reactivity in Si CVD

Thursday, October 28, 1999, 4:40 pm, Room 608

Session: Chemical Mechanical Planarization
Presenter: T. Yasuda, Joint Research Center for Atom Technology (JRCAT), Japan
Authors: T. Yasuda, Joint Research Center for Atom Technology (JRCAT), Japan
M. Nishizawa, Joint Research Center for Atom Technology (JRCAT), Japan
S. Yamasaki, Joint Research Center for Atom Technology (JRCAT), Japan
Correspondent: Click to Email
SiO@sub 2@ surfaces are chemically inert against silane molecules. This nature has made SiO@sub 2@ the most preferred mask material for selective CVD of Si, while there are other device processes that require enhanced nucleation of Si on SiO@sub 2@. Thus a technique to control the chemical reactivity of the SiO@sub 2@ surface should be useful in many aspects of device processing. This paper shows that such control is possible by treating the SiO@sub 2@ surface with a proper chlorosilane gas, SiH@sub n@Cl@sub 4-n@. Experiments were carried out using Si(001) wafers covered by an ultrathin SiO@sub 2@ layer formed by plasma or UV-ozone oxidation. Our previous studies showed that this layer acts as a mask in Si CVD using Si@sub 2@H@sub 6@.@footnote 1@ An exposure of the SiO@sub 2@-covered sample to SiCl@sub 4@ at 500 K formed surface-SiCl@sub x@ groups as confirmed by on-line Auger electron spectroscopy. We have found that Si deposition is strongly suppressed on the SiCl@sub 4@-treated SiO@sub 2@ surface under our standard CVD condition (0.05 Pa Si@sub 2@H@sub 6@; 853 K). Density of the Si nuclei is much smaller (~10@super 8@ cm@super -2@) than those observed on the as-oxidized surfaces (~10@super 9@cm@super -2@). This indicates that the surface-SiCl@sub x@ group is inert against Si@sub 2@H@sub 6@. In contrast, Si nucleation is greatly enhanced by a SiH@sub 2@Cl@sub 2@ treatment, the nucleation density reaching 6 x 10@super 10@ cm@super -2@. We have also found that electron-beam irradiation of the chlorosilane-treated surfaces prior to the CVD processing enhances Si nucleation. The minimum electron dose to induce this effect was 10 mC/cm@super 2@. Taking advantage of this effect we have achieved "resistless" selective deposition on the beam-defined parts of the SiO@sub 2@ surface. This study, partly supported by NEDO, was carried out at JRCAT under the joint research agreement between NAIR and ATP. @FootnoteText@ @footnote 1@ T. Yasuda et al., Appl. Phys. Lett. 74, 653 (1999).