Microstructure and nanoindentation hardness of Ti/TiN multilayered films

Ti/TiN multilayered films were deposited by a reactive magnetron sputtering method using a combination of a Ti target and an Ar-N-2 mixture discharge gas. The microstructure and nanoindentation hardness was characterized by v arious methods. The experimental results indicated that the hardness of mul tilayered film depends on both the modulation period and the thickness rati o between Ti and TiN layers lambda (Ti/TiN). The hardness was considerably enhanced when the modulation period was in the range 35-60 nm for lambda (T i/TiN) = 1:1 and it was up to 23 GPa. For lambda (Ti/TiN) = 1:3, the hardne ss enhancement appears in the films with the modulation period of 20-70 nm. The possible mechanism responsible for the modification of the hardness an d periods of films is also discussed. (C) 2001 Elsevier Science B.V. All ri ghts reserved.