Epitaxial garnet films by organometallic chemical vapor deposition

Abstract

Epitaxial films of Y3Fe5O12, Eu3Fe5O12, (Eu, Y)3Fe5O12, and Er3Fe5O12 l-2μm thick have been chemically vapor deposited on <111> GGG and <100> SmGG garnet substrates from 1000°C to 1200°C in an oxygen atmosphere from metal organic source compounds. These source compounds which are used here for the first time in chemical vapor deposition are tris 2, 2, 6, 6, tetramethyl 3, 5 heptanedionate complexes, (thd or M(thd)3) of the metals used. In the reactor, the individual compounds are volatilized in a helium carrier in separate source containers. The vapors are then combined, and premixed without reaction at about 300°C with a large excess of 02 and passed with high velocity, {sine wave}500 cm/sec, onto an r.f. heated substrate. The growth rate under these conditions is 0.4 - 0.8μm/hr. X-ray double diffraction, glancing angle X-ray and microprobe analyses were employed to characterize the crystallinity and stoichiometry, respectively, of the resulting garnet films. They were single crystal and exhibited a lattice constant dependent upon the rare earth to Fe ratio. The Eu containing films were not pseudomorphic probably due to the large lattice mismatch between substrate and film in most cases. The erbium iron garnet films were apparently close to pseudomorphic as determined by measured film and substrate lattice constants. © 1974 American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.