Chemical vapour deposition of high-T_csuperconducting thin films

Abstract

Fabrication of high-temperature superconducting thin films (Y-Ba-Cu-0, Bi-Sr-Ca-Cu-0, TI-Ba-Ca-CbO systems) by chemical vapour deposition (CVD) is reviewed. The key to the use of the CVD method is to find volatile compounds for the metallic constituents of superconductors. /?diketonate complexes such as acetylacetonates and dipivaloyimethanates have been successfully used as source materials. The quality of the films grown is affected by the deposition temperature, substrate material and postdeposition annealing procedure. Considerable progress has recently been made and the critical properties of cvD-grown films are now equal to those of physical vapour-deposited films.

Rare-earth oxide thin films for gate dielectrics in microelectronics

“…Similar effect has been noticed in the studies on Er 2 O 3 , where Er 2 O 3 was grown at 250-375 • C from Er(thd) 3 and O 3 [97] and at 175-450 • C from Er(CpMe) 3 [99,105,106]. Praseodymium oxide has been prepared from silylamide precursors and H 2 O [34] and more recently from Pr(mmp) 3 and H 2 O [94]. The films are amorphous, smooth and uniform, without apparent SiO 2 layer formed between Si and metal oxide (Fig.…”

“…Superior performance of La 2 O 3 has been attributed to its wide band-gap and the lowest lattice energy [42]. Jun et al have shown that MOCVD based on La(thd) 3 -tetraglyme results in La 2 O 3 films of slightly higher permittivity and lower leakage compared to La(thd) 3 and La(thd) 3 -TETEA [108]. Besides widely investigated Y 2 O 3 [39], and apart from the Gd 2 O 3 and Ga 2 O 3 studied with the III-V compound substrates [4] as well as Gd 2 O 3 and Sc 2 O 3 in GaN-channel MOSFETs [109], La 2 O 3 and Pr 2 O 3 have become the most frequently studied rare-earth oxide films.…”

“…Rare-earth oxide thin films can find numerous applications, for example, as luminescent materials, catalysts, buffer and protecting layers, and as constituents in oxide superconductors and solid oxide fuel cells [1][2][3]. This review paper will focus on the use of rare-earth oxides as gate dielectrics.…”

Evaluation of methods for application of epitaxial layers of superconductor and buffer layers

“…The measurements needed in each process were determined from the process flow schemes given earlier and from literature surveys (20,(40)(41)(42) , which were undertaken to develop a thorough understanding of each process and a comprehensive tabulation of the control parameters. After the process review, a preliminary worksheet for each process was created to provide a general description of the kinds of measurements needed as well as noting the parameter ranges when available from the literature.…”

Influence of Complexing Agents on Properties of YBa2Cu4O8Superconductors Prepared by the Sol-Gel Method

“…In order to prevent partial crystallization The importance of chemical routes in the preparation of the metal salts we chose complexing agents which conof superconducting materials is well documented for both tained a various number of hydroxo and/or carboxyl bulk and thin-film samples (1)(2)(3). Among the numerous groups, namely, ascorbic acid, citric acid, 1,2-ethanediol studies on high-T c superconducting compounds, those con-(glycol), poly(vinyl alcohol), and succinic acid.…”