Deposited metal films for imaging in scanning tunneling microscopy

The use of Au, Au/Pd, and W deposited films for imaging underlying structure, and for forming a smooth conductive base for imaging adiayers, is explored. Films of thickness less than 20 nm are studied. DC sputtering, ion beam deposition, and thermal (resistive) deposition are contrasted. All studies are conducted with the substrate held at room temperature or below. It is found that ion beam deposition gives significantly flatter films. In the case of ionic substrates held at room temperature during deposition, DC sputtered Au films are the only films that do not spontaneously crack or blister within a period of a few hours.