STUDY OF INITIAL STAGE OF SILICIDE FORMATION ON HYDROGEN-TERMINATED SILICON SURFACES

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A purpose of the present investigation was a study of initial formation mechanism of silicide on hydrogen-terminated silicon surfaces. Firstly we investigated adsorption and desorption characteristics of atomic hydrogen on clean silicons surface by using a tim-of-flight type electron stimulated desorption spectroscopy (TOF-ESD). It is believed that the terminated silicon surface by atomic hydrogen is very stable and has a surfactant effect during atomic layr epitaxy. Both of silicon surfaces of (111) and (100) planes were terminated by atomic hydrogen which generated by thermal cracking in hydrogen atomosphere of 2000 Langmuirs. The TOF-ESD which has been developed in our institute was used in-situ in order to detect the adsorbed hydrogen on silicon surfaces. Adsorption characteristtics of atomic hydrogen on clean silicon surfaces have been investigated by measuring the threshould electron energy for proton desorption, kinetic energy distribution of the desorbed protons and desorption yields for various hydrogen exposures. As a result a desorption mechnism of the proton at the first onset is due to Menzai-Gomer-Redhead model. Beside, adsorptions of hydrogen and CO on nickel surfaces were also investigeted by TOF-ESD in order to compare the nickel silicide surface.Epitaxial growth of nickel on silicon surface had different growth modes between hydrogen terminated surfaces and non-terminated surface. Namely, deposited nickel atoms on Si(100) terminated by hydrogen was diffused more quickly into the bulk than unterminated Si(100) by heating. A Ni/H/Si(100)-tereminated which was nickel rich than the unterminated one, and hydrogen was hydrogen was adsorbed less on this surface than untermianted surface.