9408779 Wu A study will be carried out of the desorption of alkali metal ions and hydrogen ions (protons) from the (100) surface of silicon under the irradiation of low fluence pulsed laser beams. The focus of this investigation is on the case where desorption results from valence instead of core level electron excitation. The motivation for this study is to understand the nature of the interaction between photons and the surface atoms and to explore the possibility of using a laser beam to modify the silicon surface by selectively desorbing certain types of adsorbed atoms. High resolution time-of-flight techniques will be used to measure the kinetic energy of desorbed ions. Doppler shifted laser-induced fluorescence techniques will be used to study the relation between desorbed neutral alkali metal atoms and their ions. % % % % Laser light has been shown to be able to deposit very fine metal lines on semiconductor wafers. This phenomenon, which is usually referred to as laser writing, has important applications in semiconductor technology. The current investigation will examine the ability of a laser beam to modify silicon surfaces by selectively removing certain types of atoms adsorbed on the silicon surface. The initial study will concentrate on the simplest and yet technologically important alkali metal and hydrogen adatoms. ***
