Junichi Suzuki

Fabrication of Diamond Films at Low Pressure and Low-Temperature by Magneto-Active Microwave Plasma Chemical Vapor Deposition.

We succeeded in fabrication of diamond films at substrate temperature of 80° C by using the magneto-active microwave plasma chemical vapor deposition (CVD) method at low pressure (0.1 Torr) with forced substrate cooling. The magneto-active microwave discharge enables us to use high-density microwave plasma under low pressure. High-density plasma-enhanced CVD under low-pressure is advantageous for low-temperature synthesis of diamond films because of decrease in thermal flux to the substrates from neutral gases heated in the plasma. Deposited films were investigated by scanning electron microscopy (SEM), Raman scattering spectroscopy, thin-film X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The fabricated films are randomly oriented polycrystalline diamond of fine crystallite size (below 100 A). The deposition rate of the diamond films decreased with decreasing substrate temperature in the range below 400° C.

Fabrication of diamond films under high density helium plasma formed by electron cyclotron resonance

Abstract Helium gas has been employed instead of hydrogen as the carrier gas to fabricate diamond films using a magneto-active plasma chemical vapour deposition (CVD) system at low pressures. Helium plasma has a much higher plasma density than hydrogen plasma and it has been shown that this promotes fabrication of good quality diamond films at low pressures. Using a gas mixture of methyl alcohol and helium, microcrystalline diamond films with a grain size smaller than 500 A have been fabricated. These microsized diamond films have been investigated by employing X-ray photoelectron spectroscopy, and features equivalent to those of natural diamond have been obtained.

Effects of plasma potential on diamond deposition at low pressure using magneto-microwave plasma chemical vapor deposition

At the low pressure of 0.1 Torr, we have controlled the plasma potential during diamond deposition for the first time using a magneto-microwave plasma chemical vapor deposition (CVD) system. The potential difference between plasma and substrate is an important factor for fabrication of diamond at this pressure. By lowering the plasma potential, high-quality diamond films have been formed. The films were evaluated by scanning electron microscope (SM) imaging, electron diffraction and Raman spectroscopy.