Si particle density reduction in Si molecular beam epitaxy using a deflection electrode

Abstract

The sticking of Si particles on the substrate surface is a serious problem for silicon molecular beam epitaxy (Si MBE) using an electron beam evaporator. We found that these particles were attracted to substrate surfaces on which a voltage was applied. Si particles were considered to have charges due to electron beam irradiation from a Si evaporator and to accelerate toward the substrate by Coulomb interaction. Because of this property, Si particles could be captured with a Ta electrode installed between an Si evaporator and the substrate. Si particle density decreased as electrode voltage increased and was unmeasurable when the electrode voltage went as far as +4 kV on the positive side and −6 kV on the negative. This technique can be applied to the particle contamination reduction not only in Si MBE but in all evaporation processes using an electron beam evaporator.