Raman spectra of TiN/AlN superlattices

TiN (4.5 nm)/AIN (3, 6, 22 nm) superlattices deposited by DC magnetron sput tering on MgO(001) at a temperature of 850 degreesC exhibit Raman signals. They indicate N and Ti vacancies (as in thick TiN) in TiN1-x layers (x = 3 +/- 2%). x is higher for the sample with 3-nm thick AIN layers, which is as cribed to N diffusion from AIN (standing close to the TiN interfaces) to Ti N. In comparison to Raman peaks of thick ALN, there are split signals of wu rzite ALN phase, and a signal from another phase, which might be defective rocksalt AIN standing close to the TiN interfaces. The Raman signals clearl y show interactions between ALN and TiN layers. (C) 2000 Elsevier Science B .V. All rights reserved.