Authors: I.D. Baikie, U. Petermann, B. Lägel

Abstract: Using a novel ultra high vacuum compatible Kelvin probe a study is made of the work function (f) changes on semiconductors and metals occurring during basic surface processing, for example, surface cleaning, sputtering, oxidation and thin film growth. It shows that damage of the 7×7 reconstruction due to Ar ion bombardment has a profound influence on the work function changes (Δf) during oxidation on the Si(111) surface, tending to decrease or even reverse the surface dipole. Also following the variable temperature oxidation kinetics of Si(111) in the range of 100–600 K and show that magnitude of the Δfpeak during the initial adsorption curve decreases in a linear fashion with increasing substrate temperature. This is interpreted as being due to the rapid onset of oxygen permeation through the surface layer at higher temperatures producing a reverse or zero net dipole. Combining work function data with a localized technique such as scanning tunneling microscopy permits monitoring of surface processes at both microscopic and macroscopic levels. In conjunction with Professor Behm’s group at Ulm University, Germany, this study monitored work function changes during evaporation of Al on Ru(0001) and show correlation between changes in f with topographic features such as island growth mechanism, monolayer formation, etc.


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