Morphological and Mechanical and Structural Characterization of Magnetron-Sputtered Aluminum and Aluminum-Boron Thin Films

O. Marcelo Suárez
University of Puerto Rico - Mayaguez, Puerto Rico, United States

Keywords: composite material, thin film, roughness, grain size, hillock, nanoindentation, scratch test

In microelectronic mechanical systems, applications where sputtered aluminum thin films are used, the film roughness and ductility become essential aspects. The present research proposes the use of magnetron sputtering furbished with a radio frequency power source to sputter aluminum and aluminum-boron thin films on crystalline and amorphous substrates. Nanoindentation allowed characterizing the films' hardness, elastic modulus, and adhesion strength, using the continuous stiffness measurement method and via a scratch test. Besides, atomic force microscopy and x-ray diffraction permitted to assess the film roughness, crystallinity, and texture. The pure aluminum target allowed producing films under similar sputtering parameters as the aluminum composite one. Our findings, supported by a range of characterization techniques, revealed how the material target, substrate type, and sputtering conditions influenced the films' mechanical behavior and structure. In summary, the films deposited using the aluminum-boron composite material target presented smaller grains and less roughness with hillock suppression.