Thermal annealing, irradiation, and stress in multilayers

The evolution of the microstructure of a TiN/B-C-N multilayered thin film during thermal annealing and irradiation has been studied by low angle X-ray diffraction and transmission electron microscopy, Stress has been determined by curvature measurements. After deposition, TIN is crystalline while B-C-N is amorphous. Thermal anneals in vacuum at 600-1000 degrees C lead to an increase of the bilayer repeat length and to a phase separation at the interfaces. After the 600 degrees C annealing, ion irradiation (Ar ions: 300 keV 1x10(15) ions/cm(2)?) causes an additional increase of the bilayer repeat length but a decrease of the quality of the interface. After annealing at 800 degrees C or 1000 degrees C, the irradiation causes a major decrease of the bilayer repeat length (more than 20% after annealing at 1000 degrees C and irradiation). The stress is highly compressive after deposition (sigma = -2000 MPa). After the 600 degrees C annealing, the stress is totally relaxed (sigma = 0) and becomes tensile after annealing at higher temperatures (sigma = + 1200 MPa after 800 degrees C annealing, sigma = + 1500 MPa after 1000 degrees C annealing), TEM confirms the decrease of the bilayer repeat length after an irradiation of the samples subjected to high temperature anneal and reveal an increase of the roughness of the interfaces. These phenomena are discussed in terms of stress driven diffusion during irradiation. (C) 1999 Elsevier Science B.V. All rights reserved.