Chemical Stability of HF-Treated Si(111) Surfaces

Abstract

Growth kinetics of native oxide on Si(111) surfaces treated in pH-modified buffered HF (BHF) solutions has been systematically studied by angle-resolved X-ray photoelectron spectroscopy. A BHF-etched (pH=5.3) Si(111) surface has no Si-F bonds and dose not oxidize for 300 min in clean room air. FT-IR-attenuated total reflection (ATR) measurements of Si-H bonds existing on the BHF-treated Si(111) surface have revealed that the surface is nearly step-free and atomically flat. This explains the chemical stability of the Si(111) surface.

Chemical treatment effect of Si(111) surfaces in F-based aqueous solutions

“…It is well known 2-7 that HF ͑NH 4 F͒ etching results in the removal of the surface oxide and leaves behind Si surfaces terminated by atomic hydrogen. More recent study on HF ͑buffered-HF͒ processing 24 reports that a completely flat, H-terminated surface without fluorine bonds or a rather rough, H-terminated surface with enough fluorine bonds is chemically stable against oxidation. Such adsorbed chemical species may affect the ellipsometric data and result in modification of the dielectric function.…”

Nanometer-scale field-induced oxidation of Si(111):H by a conducting-probe scanning force microscope: Doping dependence and kinetics

“…As a result, hydrophobic, H-terminated, and atomically stepped surfaces with flat terraces are formed which are well stabilized against oxide formation in air ambient. 11,12 A native oxide thickness well below 0.1 nm is expected to form within 3 h, the timescale of our experiments. 12 In contrast, on Si͑100͒ atomic scale roughness remains after chemical treatment.…”

“…11,12 A native oxide thickness well below 0.1 nm is expected to form within 3 h, the timescale of our experiments. 12 In contrast, on Si͑100͒ atomic scale roughness remains after chemical treatment.…”

Kinetics of field-induced oxidation of hydrogen-terminated Si(111)

“…10 In contrast, in most cases atomic scale roughness remains on Si͑100͒ after chemical treatment. Before oxidation, oxide-free H-terminated Si͑111͒ surfaces ͓Si͑111͒:H͔ were prepared on Czochralski ͑Cz͒ grown wafers.…”