STUDY OF IN-SITU SURFACE CLEANING FOR SI AND SIGE EPITAXY ON SI WITH A NOVEL ION-BEAM VAPOR ASSISTED DEPOSITION TECHNIQUE

Ion beam vapor deposition is a new technique to grow Si and SiGe layer s on Si substrates at low temperatures. The in situ surface cleaning p rior to the deposition is a crucial step in the epitaxial growth of Si and SiGe films and is achieved by Ar ion bombardment with substrates kept at ambient temperature. A high temperature annealing (800 degrees C) is needed to repair the damage caused by this bombardment, We stud ied the effects of ion beam energy and the substrate temperature durin g the in situ cleaning on the quality of the grown films. An ion beam energy of 150-200 eV is found to be sufficient to clean the surface fo r epitaxial growth. While the films deposited on properly cleaned surf aces are epitaxially grown, the inadequately cleaned surface leads to the formation of polycrystalline layers especially at low substrate te mperatures.