Effects of scandium addition on electrical resistivity and formation of thermal hillocks in aluminum thin films

• Published in: Thin solid films Vol. 519; no. 11; pp. 3578 - 3581
• Main Authors: Lee, Sheng-Long, Chang, Jeng-Kuei, Cheng, Yin-Chun, Lee, Kent-Yi, Chen, Wen-Chi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31.03.2011; Elsevier
• Subjects: Aluminum; Aluminum alloy; Annealing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Density; Deposition by sputtering; Electrical properties of specific thin films; Electrical resistivity; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Grain size; Magnetron sputtering; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Resistivity; Scandium; Scanning electron microscopy; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal hillock; Thin film structure and morphology; Thin films; Transmission electron microscopy; Thermal hillock; Magnetron sputtering; Transmission electron microscopy; Resistivity; Scandium; Aluminum alloy; Grain boundaries; Electrical conductivity; Sputtering; Thin films; Cathode sputtering; Physical vapor deposition; Thermal stresses; Grain size; Scanning electron microscopy; Stress analysis; Crystal defects; Annealing; Crystallization; Aluminium; Quantity ratio; Aluminium additions; Electric resistivity; Thermal analysis; Sputter deposition
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.01.272

This study investigates the effects of doping aluminum (Al) films with minor amounts of scandium (Sc) on the electrical resistivity and the formation of thermal hillocks. The pure Al and Al–Sc films, prepared via sputtering deposition, before and after isochronal annealing are examined using a scanning electron microscope and a transmission electron microscope. In-situ thermal stress analyses of the films are also carried out. The grain size of the as-deposited films is reduced by addition of Sc. Moreover, the Sc can immobilize the grain boundaries, retarding grain growth and re-crystallization of the films during annealing. Although the as-deposited Al–Sc films show higher resistivity than that of a pure Al film, the former is significantly decreased after annealing at 300°C. The hillock density dramatically reduces with increasing the Sc concentration in the films. Average size of the hillocks in Al–Sc films clearly increases when the temperature is elevated.