FLUORINE-CONTAINING SPECIES ON THE HYDROFLUORIC-ACID ETCHED SILICON SINGLE-CRYSTAL SURFACE

The chemical structure and property of fluorine-containing species on the hydrofluoric acid (HF) etched Si surface was examined by use of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The fluorine content on the surface was found to increase with increase of HF concentration. A silicon surface etched by 50% HF has fluorine of 2.6 x 10(14) atoms/cm2 as Si-F. Most of the Si-F boundings are rapidly hydrolyzed to Si-OH by rinsing the wafer in water. Thus prepared Si-OH groups are found to be useful as active sites for chemical modification of the bare silicon single-crystal surface. The Si-F was observed not to influence the oxidation rate of HF etched silicon surface.