Fine Grain Metal film Deposition
Original Publication Date: 1980-Sep-01
Included in the Prior Art Database: 2005-Feb-13
Fine gain films of superconductive metal are vapor-deposited at liquid nitrogen temperature, i.e., 77 degrees K. These films suffer from pinholes and blisters which develop after a certain time under room temperature. The defects are attributed to gases which are trapped in the film at liquid nitrogen temperature and which are set free at room temperature. The gases are residues in the reactor from a prior sputter-cleaning step. Workers in the field were trying to improve the films by lowering the vacuum pressure. This takes additional effort, equipment and care. If the substrate temperature, which was 77'K only for the convenience of boiling nitrogen, is made somewhat higher, the residual gases will condense not on the substrate but on cooler surfaces inside the reactor.