著者

服部 伴之 山口 哲央 間嶋 俊雄 寺嶋 和夫 吉田 豊信

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.63, no.1, pp.68-73, 1999

被引用文献数

3

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Hot cluster epitaxy (HCE) is a novel high-rate epitaxial growth mechanism discovered in the study of the plasma flash evaporation method. In HCE, the main deposition species are thermally activated, nanometer-scale clusters (hot clusters), which have unique characteristics such as high internal energy and high sticking probability even at high substrate temperature. Actually, with HCE, deposition of YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7&minus;<I>x</I></SUB> epitaxial films at a growth rate of 16 nm/s on the SrTiO<SUB>3</SUB> substrate has been achieved. However, films thicker than 2 &mu;m could not be obtained so far. In this paper, we discuss the &ldquo;charge-up&rdquo; effect of clusters and insulating substrates in a plasma environment as a retarding factor for film growth. Probe measurements and the biasing deposition clarified the charge-up of clusters were charged up during deposition. It was found that more than 60% of the clusters were negatively charged. By using conductive substrates of Nb doped SrTiO<SUB>3</SUB>, or changing Ar composition in Ar-O<SUB>2</SUB> plasma, we could deposit monolayer-smooth epitaxial YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7&minus;<I>x</I></SUB> films thicker than 3 &mu;m, with excellent properties; the full width less than 0.14&deg; at half maximum of the X-ray rocking curve of the (005) peak, and the superconducting transition temperature of 92 K. These results suggest the future role of HCE in epitaxial thick film deposition.