Epitaxial Growth of Metals on Rocksalt Faces Cleaved in Vacuum. I

抄録

The epitaxial growth of Ni, Cu, Ag, Au and Al on NaCl crystals cleaved in vacuum has been studied. When the crystals are cleaved in ordinary high vacuum (10⁻⁴–10⁻⁵ mmHg), a considerable lowering of the epitaxial temperatures for the parallel epitaxy takes place for the first four metals, as compared with the case in which the crystals are cleaved in air. The temperature differences due to this lowering are 270°C for Ni, 250°C for Cu, 150°C for Ag, and 120°C for Au. Al has been found for the first time to form single crystal films with the (111)-plane parallel to the substrate at the substrate temperature of 100°C. When the degree of vacuum is improved to ultrahigh vacuum (10⁻⁷–10⁻⁹ mmHg), on the other hand, the (001) preferred orientation deteriorates and the (111) preferred orientation appears for Cu, Ag and Au, the latter orientation becoming conspicuous with rising temperature for Au and Ag, while no considerable change arises for Ni and Al with the improvement of the degree of vacuum.