Comparison of deposition methods for ultra thin DLC overcoat film for MR head

Abstract

Abstract To improve overcoat films for giant magnetoresistive (GMR) heads, we developed a commercial multi-film deposition system capable of performing three diamond-like carbon (DLC) deposition methods, i.e. electron cyclotron resonance-chemical vapor deposition (ECR-CVD), ion beam deposition (IBD), and filtered cathodic vacuum arc (FCVA); pre-cleaning with Ar sputtering etch; and Si adhesion layer deposition. In comparative evaluations of 50-nm-thick films deposited on a Si wafer, ta-C film by FCVA shows higher hardness/density compared to DLC films by ECR-CVD or IBD. Scratch testing and electron spectroscopy for chemical analysis (ESCA) measurements of films prepared by ECR-CVD and FCVA on an Al 2 O 3 TiC substrate indicate that substrate bias enhances mixing between the carbon film and either the Si film or Al 2 O 3 TiC substrate such that good adhesion occurs.