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Single Crystal Films of Lithium Niobate

IP.com Disclosure Number: IPCOM000074911D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Sadagopan, V: AUTHOR

Abstract

An RF sputtering process is described for producing thin, single-crystal films of lithium niobate which possess optical properties similar to that obtained in bulk single crystals.

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Single Crystal Films of Lithium Niobate

An RF sputtering process is described for producing thin, single-crystal films of lithium niobate which possess optical properties similar to that obtained in bulk single crystals.

A single-crystal substrate is introduced into a RF sputtering apparatus. The single-crystal substrate must exhibit a favorable lattice match to reduce stress in the final film and to insure epitaxial growth of the sputtered lithium niobate. A single crystal of grown lithium niobate or a-cut or c-cut sapphire are suitable substrates.

A hot pressed cathode of lithium niobate is positioned parallel to and spaced from the substrate in the RF sputtering apparatus. The cathode should be stoichiometric in nature and should be of such purity that the resulting single- crystal films are also stoichiometric in nature and contain no impurities which would adversely affect their operation. A shutter is movably positioned between cathode and substrate.

The sputtering apparatus is evacuated to a pressure of approximately 2 x 10/-8/ torr and undesired gases are gettered from the apparatus. Then argon is introduced at a pressure in the range of 25 to 44 microns, and preferably 32 microns.

The lithium niobate cathode is presputtered for 15 to 30 minutes to insure its cleanliness, with the shutter shielding the substrate. The cathode is then cooled for 15 minutes to avoid over heating and consequent spalling and breakage, as well as a loss of oxygen from the lithi...