Structural analysis of rf and dc sputtered Nb/sub 3/Ge thin films containing oxygen

Journal Article · Wed Mar 01 04:00:00 EST 1978 · J. Vac. Sci. Technol.; (United States)

DOI:https://doi.org/10.1116/1.569551· OSTI ID:6807858

Alessandrini, E I; Laibowitz, R B; Tsuei, C C

Using electron microscopy, diffraction, microprobe, scanning microscopy, and nuclear back-scattering techniques to analyze rf and dc sputtered N/sub 3/Ge thin films, it was found that the film structure was strongly dependent on film preparation methods. Amorphous Nb/sub 3/Ge films were prepared by both sputtering techniques, on substrates held at liquid nitrogen temperature. Identical crystallization heat treatments were then carried out in a He furnace at 750/sup 0/C for 65 h. Analyses by nuclear back-scattering indicated that crystallized rf-prepared films contained about three times as much oxygen as crystallized dc films. Structure studies showed that although both types of crystallized films exhibited the A-15 structure, the data on the rf films indicate the presence of the crystalline oxide, Nb/sub 2/O/sub 5/. In addition, the lattice parameter for the rf film was slightly smaller * dc-prepared films while the grain size of the former is about 10 times larger. These data appear to be correlated to differences in the superconducting transition temperature of both types of films. A high T/sub c/ (approx.16 K) was observed for rf-prepared samples. The annealed dc-sputtered films did not become superconducting for temperatures above 1.5 K. In summary, the results of this work indicate that large grain size is conducive to high T/sub c/ superconductivity in Nb--Ge system and provide some evidence for oxygen stabilization of the high T/sub c/A-15 phase.

• Research Organization: IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598
• OSTI ID: 6807858
• Journal Information: J. Vac. Sci. Technol.; (United States), Journal Name: J. Vac. Sci. Technol.; (United States) Vol. 15:2; ISSN JVSTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
AMORPHOUS STATE
ANNEALING
CHALCOGENIDES
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
CRYSTALLIZATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
FLUIDS
GERMANIUM ALLOYS
GRAIN SIZE
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
LATTICE PARAMETERS
MICROSTRUCTURE
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE STUDIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SIZE
SPUTTERING
STABILIZATION
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TYPE-II SUPERCONDUCTORS