13.56 MHz radio frequency plasma properties on hemispheric electrodes and diamond-like carbon films deposition on three-dimensional polyurethane diaphragms

Abstract

The characteristics of the radio frequency (rf) plasma that could hold an entire hemispheric polyurethane diaphragm generated using the hemispheric-type electrode were investigated. The plasma states were measured using Langmuir probe. Although the common rf plasma chemical vapor deposition technique using planar electrodes makes it difficult to apply uniform plasma to three-dimensional structures, the hemispheric-type electrode process could uniformly hold a hemispheric polyurethane diaphragm at self-bias voltage. As a result, this process could uniformly keep the ion sheath on the diaphragm. In case of using this process for diamond-like carbon (DLC) film deposition, the DLC film was deposited uniformly on the diaphragm at approximately 300nm. Besides electron temperatures and electron number of densities were similar to the behavior of common rf plasma. This means that the characteristics of plasma are kept in the same states even if the plasma form is controlled using such a hemispheric-type electrode. Based on these results, this hemispheric-type electrode process was observed to be quite applicable to three-dimensional insulator structures.