| 摘要 |
PURPOSE:To obtain a laser mirror film having strong bonding strength with a substrate and high reflectivity by keeping acceleration voltage constant and increasing ion currents first and reducing them later. CONSTITUTION:When acceleration power supplies 11 and an ionization power supply 13 are adjusted and evaporation is conducted while acceleration voltage is brought to a value such as 5kV and ionization currents to a value such as 1.0muA/cm<2> or more first, an ionization cluster is given large kinetic energy because it is accelerated at 5kV and the ionization cluster collides with a substrate 10, impurities adhering on the surface of the substrate 10 are sputtered, the surface of the substrate 10 is purified, and the substrate 10 and an evaporating film 12 are bonded firmly. When ionization currents are lowered up to 0.4muA/cm<2> or less as acceleration voltage is left as it is, the energy of the ionization cluster reduces. Consequently, the number of evaporating atoms sputtered from the ionization cluster decreases, and an evaporation rate increases. The ionization of a residual gas, concentration to and a collision with the central section of the substrate by acceleration voltage and the formation of a spotty heterogeneous section are minimized because ionization currents are reduced. |
