Oh-Hun Kwon

Magnetic characterization of intermetallic compound FePt and FePtX (X=B, Ni) thin films

Abstract VSM rotational transverse magnetization technique was used to characterize the anisotropy field of FePt and FePtX (X=B, Ni) thin films with comparison to commercial CoCrTaPt media. Anisotropy energy was derived. H c /H k was used as an indicator for coherent rotation of a single domain. Interactions between magnetic domains were characterized by Kelly–Henkel plot. Interactive field factor was used as a coupling factor similar to δM . Correlations between coercive force, magnetic anisotropy of grains, and the degree of magnetic isolation among grains were discussed. B and Ni had been added as diluting agent to the FePt system to decrease saturation magnetization, coercivity, anisotropy field and anisotropy energy. These doping elements also decrease the magnetic coupling between neighboring domains, and promote coherent rotation inside each domain.

Characterization of Static-dissipative Ceramics for ESD and Contamination Control Purposes

Electrostatic charge and discharge is one of the major contributors to the reliability and yield loss of microelectronic device manufacturing. As semiconductor or other microelectronic devices become smaller, are operated at faster speed, and are demanded for lower cost, their sensitivities to electrostatic discharge (ESD) events have gradually out-paced the protections available from traditional ESD control measures, such as grounding or ionization. This is especially true for those devices identified as Class 0 by ESDA. Using static- dissipative materials is one of the viable solutions to protect ESD sensitive devices during their manufacturing. Among static-dissipative materials, dissipative ceramics have many unique advantages, such as homogenous electrical properties, high strength and stiffness, excellent wear and heat resistance, and no tendency to out-gas. In this paper the relationship between tunable electrical resistivities and corresponding charge dissipation behaviors of ESD safe ceramics is established. Meantime, the potential of ESD safe ceramics to be particle and metal contamination free is also demonstrated through particle count, scratch/wear test, and chemical corrosion test.