Characterisation of HF-last Cleaning of
Ion-Implanted Si Surfaces
E. Kondoh a), M.R. Baklanov b), F. Jonckx c), and K. Maex d)
IMEC, Kapeldreef 75, 3001 Leuven, Belgium.
Tel: +32-16-281678, Fax: +32-16-281315, e-mail: kondoh@imec.be
a) from 1 July 1998, Center for Microelectronic Systems, Kyushu Institute of Technology, 820-8502 Fukuoka, Japan.
b) On leave from Institute of Semiconductor Physics, Novosibirsk, Russia.
c) Present address, Alcatel Mietec, 9700 Oudenaarde, Belgium.
d) Also at INSYS, Katholieke Universiteit Leuven, Belgium
Page by E. Kondoh
kondoh@ccn.yamanashi.ac.jp http://www.ccn.yamanashi.ac.jp/~kondoh
ABSTRACT
Issues of HF-last cleaning of implanted silicon are studied. Contact angle measurement and ellipsometry are employed and the results are discussed based on SiO2 and Si surface chemistry. The cleaning of BF2-implanted wafers is not straightforward because of low etch rate of surface oxide and slow removal of surface hydroxyl groups. This problem is not significant in the case of As-implanted silicon, however the surface is found to oxidise faster than that of BF2 or non-implanted silicon. Oxygen chemisorption starts at the silicon surface immediately after HF etching. Surface charge measurement can be a good alternative to contact angle measurement for the characterisation of silicon surface cleaning.
Native oxide growth on As-doped Si
Contact angle changes with HF dip time on p-Si wafers
