Hydrogen Free, High sp3 Content DLC Films Produced by Pulsed Laser Ablation of Amorphous Graphite

Abstract

Pulsed laser deposition is a unique technique for the deposition of a wide variety of thin films. These films include magnetic and optical films, novel semiconductors, high temperature superconductors, and diamond-like carbon films. Amorphous Carbon material is evaporated from a solid target and ionized by a high-energy KrF laser and ejected as a plasma plume. The plume expands outwards and deposits the target material on a silicon substrate. Plasma and flow parameters in this plume determine the quality of the film deposited on the substrate. In these experiments, a quadruple Langmuir probe is used to determine various plasma properties in the plume as a function of laser energy density on target, laser spot size on the target and probe position from target. These properties include electron temperature, ion flow speed, ion kinetic energy, plume peaking parameter, and ion density. Film analysis was conducted by electron energy loss spectroscopy (EELS) indicating that DLC films have been successfully deposited with an sp3 concentration as exceeding 72%.