ATOMIC-HYDROGEN-INDUCED RESTRUCTURING OF THE SI(100)(2X1)-K SURFACE

The interaction of hydrogen atoms with the Si(100)(2 X 1)-K surface has been studied by using thermal desorption and electron energy loss spectroscopy. We have found that hydrogen adsorption induces the formation of potassium hydride islands at 90 K for even one-monolayer coverage of K, indicative of restructuring of the K-covered surface induced by hydrogen adsorption. The proposed reaction mechanism is as follows: incoming H atoms react with surface SiK species to generate surface SiH species and K atoms with the K atoms subsequently reacting with incoming H atoms to form potassium hydride. We discuss the relevance of the present results to the reaction of the metal-modified Si surface with hydrogen atoms.