Yohko Naruse

The effect of hydrogen- and oxygen-plasma treatments on dielectric properties of amorphous carbon nitride films

Abstract Amorphous carbon nitride (a-CN x ) films made by a reactive sputtering of a carbon target with nitrogen plasma shows high resistivity and high electrical breakdown field. Therefore, a-CN x is a good material as a dielectric material. In this paper, the effects of hydrogen-plasma and oxygen-plasma treatment to the dielectric properties of a-CN x films were studied, discussed and compared. A cyclic process of the deposition of a thin a-CN x film and hydrogen- and oxygen-plasma treatment, which is called the layer-by-layer process (LL), were used to make LLa-CN x and LLa-CN x O y films, respectively. Comparing the results of capacitance made of a-CN x , LLa-CN x , and LLa-CN x O y the most effective treatment to get smaller dielectric constant materials at present was to use hydrogen plasma treatment.

Amorphous carbon nitride deposition by nitrogen radical sputtering C+N+O+H

Abstract Amorphous carbon nitride films a-CNx were prepared by a nitrogen radical sputtering of a carbon target. A-CNx films were treated by atomic hydrogen or by an oxygen plasma, using a layer-by-layer method, forming LLa-CNx or LLa-CNxOy. These a-CNx films show large photosensitivity, high resistivity and low dielectric constants. Possible applications are also discussed briefly.

Preparation and properties of amorphous carbon oxy-nitride films made by the layer-by-layer method

Abstract Amorphous carbon oxy-nitride films, a-CN x O y , are attractive for obtaining low dielectric constant materials and also for preparing photoconductive materials with a higher optical band gap than amorphous carbon nitride films, a-CN x . We found that oxygen plasma processes on a-CN x have two effects: etching and oxidation in the preparing process of amorphous carbon oxy-nitride films a-CN x O y . Because it was not possible to make films by mixing a small amount of oxygen to nitrogen as a reacting sputter gas, we have prepared LLa-CN x O y in a layer-by-layer process, which consists of a cyclic process of deposition of a thin amorphous layer a-CN x by nitrogen-radical sputtering of a carbon target and of an oxygen plasma treatment on a-CN x . By a layer-by-layer process of 60–120 cycles, we have tried to homogenize the distribution of oxygen atoms in LLa-CN x O y . Defect densities, infrared absorption spectra and UV-Vis absorption spectra to obtain the optical energy gap E o were used to characterize LLa-CN x O y films. From infrared spectra, the peaks related to carbon and oxygen were confirmed to increase in LLa-CN x O y films. LLa-CN x O y with Tauc optical energy gaps up to 2.67 eV were prepared, whose value was larger than the 1.5–2-eV value of a-CN x .

Preparation and properties of amorphous carbon oxynitrides a-CNxOy films made by a nitrogen radical sputter method and by the layer-by-layer method

Abstract : We have tried to prepare amorphous carbon oxynitrides (a-CN(x)O(y)) films by the oxygen radical treatment (ORT) of amorphous carbon nitrides (a-CN(x)) and also by the layer-by-layer method. Properties of a-CN(x)O(y) films were studied with x-ray photoelectron spectroscopy (XPS), photothermal deflection spectroscopy (PDS), ultraviolet-visible (UV-VIS) optical transmittance spectra Raman spectra and electron spin resonance (ESR). Oxygen radical affects to a-CN(x) by etching, termination of defects and oxidation. A-CN(x)O(y) films are interesting for the application to luminescent materials and also to low dielectric constant materials.