Alex A. Wernberg

Preparation of zinc sulfide thin films by ultrasonic spray pyrolsis from bis(diethyldithiocarbamato) zinc(II)

Abstract Thin films of zinc sulfide were prepared by ultrasonically spraying a toluene solution of bis(diethyldithiocarbamato)zinc(II) onto silicon, sapphire and gallium arsenide substrates at 460–520 °C. The films prepared on silicon or sapphire were found to have a highly oriented hexagonal structure, while those deposited onto cubic (100) gallium arsenide showed a highly oriented cubic structure. The films were characterized by X-ray diffraction analysis, ellipsometry, scanning electron microscopy, and IR spectroscopy.

Epitaxial growth of lithium niobate thin films from a single‐source organometallic precursor using metalorganic chemical vapor deposition

Lithium niobate thin films were deposited on (0001) sapphire using metalorganic chemical vapor deposition. An organometallic compound, formed by reaction of lithium dipivaloylmethanate and niobium(V) ethoxide, was used as a single‐source precursor. The epitaxial nature of the films was established by x‐ray diffraction and Rutherford backscattering analyses (RBS).

Solid‐phase epitaxial growth of lithium tantalate thin films deposited by spray‐metalorganic chemical vapor deposition

We demonstrate the solid‐phase epitaxial crystallization of thin films of lithium tantalate deposited on lithium niobate and sapphire substrates. An organometallic compound, formed by reaction of lithium dipivaloylmethanate and tantalum(V) ethoxide, is used as a single‐source precursor for the deposition of amorphous thin films of lithium tantalate using a spray‐metalorganic chemical vapor deposition process. Annealing of the amorphous films results in their epitaxial alignment with respect to the underlying LiNbO3 or Al2O3 substrates. X‐ray diffraction, ion channeling, and scanning electron microscopy are used to evaluate and compare the crystalline quality of the films produced by this solid‐phase epitaxial process to films that are crystalline as deposited.

Improved solid phase epitaxial growth of lithium tantalate thin films on sapphire, using a two‐step metalorganic chemical‐vapor deposition process

Epitaxial lithium tantalate thin films were grown on sapphire substrates by metal‐organic chemical‐vapor deposition using a two‐step growth process. After an initial thin (≊30–100 A thick) amorphous buffer layer of LiTaO3 was deposited and annealed to induce crystallization by solid phase epitaxy (SPE), a second, thicker amorphous lithium tantalate layer was deposited and also crystallized using SPE. The use of the buffer layers substantially improved the crystalline quality of the heteroepitaxial films, with the thickest buffer layer providing the best results. The films were characterized by ion channeling, x‐ray diffraction and scanning electron microscopy.

Single crystalline growth of LiNbO3 on LiTaO3 by spray metalorganic chemical vapor deposition using the single source precursor LiNb(OEt)6

Abstract Single crystal LiNbO 3 has been deposited on a z -cut LiTaO 3 substrate by a spray metalorganic chemical vapor deposition (MOCVD) process using the single source precursor LiNb(OEt) 6 . The surface morphology of the film has been characterized by scanning electron microscopy and its single crystal quality was established by X-ray diffraction (θ−2θ scans, rocking curve measurements and pole figure analysis) and Rutherford backscattering spectrometry combined with ion channeling.

Epitaxial growth of gallium arsenide thin films by spray pyrolysis using a single-source organometallic precursor

Abstract Epitaxial films of gallium arsenide were grown on (100) GaAs at 520–540°C from the single source organometallic precursor [(n-Bu) 2 Ga(μ-As(t-Bu) 2 )] 2 using a modified spray pyrolysis process. The epitaxial nature of the films was established by X-ray diffraction and Rutherford backscattering analyses. Secondary ion mass spectrometry analysis indicated an accumulation of carbon and oxygen at the film-substrate interface. Resistivity and Hall effect measurements suggest that the films are highly compensated.

Ultra-high vacuum metalorganic chemical vapor deposition of GaAs thin films onto Si(100) using a single-source precursor

Abstract Films of gallium arsenide were deposited under ultra-high vacuum (UHV) conditions onto a silicon (100) substrate at 400 °C using a single organometallic precursor containing both Group III and Group V elements. Characterization of the films by Auger electron spectroscopy indicates that carbon is incorporated into the film in the initial stages of film growth and that the films are arsenic-deficient.