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Low Temperature Epitaxy and Polycrystalline Growth of Niobium on Sapphire

IP.com Disclosure Number: IPCOM000038889D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+3]

Abstract

Niobium (Nb) has been found to grow epitaxially at room temperature when prepared by ion beam sputter deposition onto sapphire substrates oriented with (0001) perpendicular to the surface. The X-ray pole figure technique was used to characterize both as-deposited films and films deposited during simultaneous ion bombardment. The presence of a secondary beam causes a drastic change in the orientation of the Nb films. The substrates used in gathering all of the experimental data were (0001) oriented one-inch diameter sapphire wafers. The substrates were cleaned by scrubbing, using a surface-active decontaminating detergent, followed by ultrasonic cleaning and a deionized water rinse. The samples were then loaded into the sputtering chamber which was evacuated to a base pressure in the 1-2 x 10-7 Torr range.

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Low Temperature Epitaxy and Polycrystalline Growth of Niobium on Sapphire

Niobium (Nb) has been found to grow epitaxially at room temperature when prepared by ion beam sputter deposition onto sapphire substrates oriented with (0001) perpendicular to the surface. The X-ray pole figure technique was used to characterize both as-deposited films and films deposited during simultaneous ion bombardment. The presence of a secondary beam causes a drastic change in the orientation of the Nb films. The substrates used in gathering all of the experimental data were (0001) oriented one-inch diameter sapphire wafers. The substrates were cleaned by scrubbing, using a surface-active decontaminating detergent, followed by ultrasonic cleaning and a deionized water rinse. The samples were then loaded into the sputtering chamber which was evacuated to a base pressure in the 1-2 x 10-7 Torr range. The pressure in the chamber during deposition was 2 x 10-4 Torr. The films were grown by ion beam sputter deposition. An Ar+ ion beam of 1800 eV energy sputtered a Nb target to provide a flux of atoms arriving at the substrate. A second ion source was positioned so that direct bombardment of the substrate was possible. This "substrate beam" impinged at a glancing angle of 0 = 20o to the substrate with Arions at an energy of 200 eV. A radiant heater placed behind the substrate platform enabled substrate heating up to 500oC. Fig. 1 is a schematic of the experimental set-up. An extensive schedule of experiments was performed, both with and without substrate bombardment, with substrate temperatures of 25oC, 200oC, and 400oC. In order to better understand the mechanism behind ion bombardment-induced orientation change, additional experim...