Interface structure and adhesion of sputtered metal films on silicon: The influence of Si surface condition

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 11; no. 2; pp. 319 - 324
• Main Authors: Kondo, Ichiharu, Yoneyama, Takao, Kondo, Kenji, Takenaka, Osamu, Kinbara, Akira
• Format: Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 01.03.1993
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); ADHESION; INTERFACE STRUCTURE; NICKEL; THIN FILMS; Ti; ARGON IONS; SPUTTERED MATERIALS; Si; SILICON; ETCHING; ION IMPLANTATION; TITANIUM; Non metal; Crystal growth; Magnetron; Semiconductor materials; Support; Operating mode; Transition metal; Chemical etching; Experimental study; Adhesion; Surface treatment; Thin film; Interface structure; Argon Atomic ions; Irradiation; Titanium; Silicon; Pretreatment; Cathodic sputtering
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.578732

Ni(100–1000 nm)/Ti(250 nm) films were prepared by dc planar magnetron sputtering on Si(100) surfaces. Interface structures between Ti and Si and adhesion of the Ti films to Si after different surface pretreatments have been investigated. Before the film deposition, the Si substrate received an Ar ion bombardment or a chemical etching treatment. In the case of the Ar ion bombardment, we have investigated the effect of the cathodic voltage. A low cathodic voltage (50 V) resulted in high adhesion. The results by Rutherford backscattering spectroscopy showed that the amount of Ar incorporated in the Si surface during the Ar ion bombardment is increased with the cathodic voltage. The existence of Ar at the interface between the Si substrate and the Ti–Si mixed layer seems to lower the adhesion. In the case of the chemical pretreatment, we have investigated the effect of the exposure time in the atmosphere after the chemical etching treatment. A shorter exposure time (within 1 h) has been found to be preferred to a longer exposure time. The results of Auger electron spectroscopy and the peeling test showed that the exposure time is related to the oxide thickness, the Ti–Si alloy thickness, and the adhesion. It is considered that the stable SiO2 formation prevents the Ti–Si mixed layer formation and lowers the adhesion.