CVD OF METAL ORGANIC AND OTHER RARE-EARTH COMPOUNDS

Three major applications have been found for rare‐earth compounds in Metal Organic Chemical Vapour Depostion (MOCVD) or Chemical Vapour Deposition (CVD). Yttrium 2,2,6,6‐tetramethyl‐3,5‐heptanedionates and 6,6,7,7,8,8,8‐heptafluoro‐2,2‐dimethyl‐3,5‐octanedionates have been used in conjunction with barium and copper(II) β‐diketonates to deposit YBa2Cu3O7−δ as superconducting thin films. Rare‐earth fluorides and chlorides have been used for CFD doping of rare earths into MOCVD‐deposited ZnS, whilst yttrium chloride has been used, with barium iodide and copper(I) chloride, to produce YBa2Cu3O7−δ superconducting material by CVD. Lanthanoid (Ln) tris(cyclopentadienyl) compounds, Ln(C5H5)3 or Ln(C5H4Me)3, have been used for doping of rare earths into 13–15 (III–V) semiconductors. Their volatility, structure/volatility relationships, and preparations are discussed. Possible alternative reagents and problems to be faced in doping 12–16 (II–VI) semiconductors are also considered. Copyright © 1990 John Wiley & Sons Ltd.