Validity of Bragg's rule in sputtered superconducting NbN and NbC films of various compositions
From international conference on ion beam surface layer analysis; Yorktown Heights, NY (18 Jun 1973). Niobium nitride layers were produced by reactive sputtering in an argon- nitrogen plasma. Compositions were varied by altering the nitrogen partial pressure during the sputtering process. Changes in composition were determined by measuring the niobium peak height at the layer surface in back-scattered spectra, as well as by measuring the superconducting transition temperature T/sub c/ in homogeneous layers. These results are compared wtth niobium peak heights calculated as a function of the ratio of the number of nitrogen atoms to niobium atoms, using experimental and theoretical stopping cross sections for /sup 4/He/sup +/ ions in niobium and nitrogen. Assuming the validity of Bragg's rule in this calculation the measured values are found to be 7 to 8% smaller than those calculated.. As uncertainties exist in present values of the stopping cross sections of Nb and N it is concluded that the observed deviation is too small to indicate whether or not Bragg's rule is applicable. During the production of NbC layers in an Ar plasma the Nb target was covered by a perforated carbon plate. Stoichiometric layers have been produced with T/sub c/ values similar to that for bulk samples. The deviation between calculated and measured Nb peak heights is of the same order of magnitude as that found for NbN. (auth)
- Research Organization:
- Kernforschungszentrum, Karlsruhe, Ger.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-29-025447
- OSTI ID:
- 4353642
- Journal Information:
- Thin Solid Films, v. 19, no. 2, pp. 217-226, Conference: International conference on ion beam surface layer analysis, Yorktown Heights, NY, 18 Jun 1973; Other Information: Orig. Receipt Date: 30-JUN-74
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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