Motoya Kumagai

Deposition of amorphous carbon using a shunting arc discharge

Abstract Using the shunting arc discharge, preparation of a hydrogen free diamond-like carbon (DLC) film is demonstrated. The substrate is immersed into the plasma, and a series of pulse voltage is applied to the substrate was synchronized with a generation of the shunting arc with a peak current of 1.7 kA. The prepared film has a smooth surface with a dark blue color, with only droplets even without filtering system. The film is amorphous and a typical Raman spectrum with the D and G band is observed. The film thickness is largest in a voltage range of −4 to −8 kV, from which it is inferred that the carbon ions contribute to the film preparation.

Ion extraction from carbon shunting arc plasma

The ion current characteristics of the shunting arc discharge are described in this letter. A carbon rod with 2 mm diameter and 40 mm length was employed for arc generation. The combination of the shunting arc and the negative pulse voltage applied to target is promising for plasma-based ion implantation and deposition for metallic or semimetallic three-dimensional materials. The delay time, which is defined as the time between the start of the arc current and applying the pulse voltage, was varied. The ions are extracted from the shunting arc plasma by applying a pulsed bias voltage to a target set nearby the arc source. The arc current lasts 40 μs, of which peak is 1.7 kA. The extracted target current has a sharp peak at the initial stage, followed by a stationary state. The stationary current decreases with increasing the delay time and increases with increasing the bias voltage. Under the assumption of a collisionless ion sheath, the plasma density was estimated. At the boundary between the ion sheath...

Characteristics of shunting arc discharge for carbon ion source

Abstract The criteria of initial resistance of carbon rod for shunting arc ignition are described in this article. The five different resistances were used. The rods are 40 mm in length and 2 mm in diameter. The carbon rod was set in the vacuum and was initially heated up with a pulsed current supplied by a charged capacitor with a capacitance of 20 μF, followed by a self-ignition. The heating energy is almost independent of the charging voltage of the capacitor. The heating energy increases with decreasing the rod resistance, whereas the energy deposited in the plasma and the utilizing efficiency of the charged energy in the capacitor decreases.

AMORPHOUS CARBON FILM DEPOSITION BY MAGNETICALLY-DRIVEN SHUNTING ARC DISCHARGE

A magnetically driven shunting arc discharge as a pulsed metal/solid plasma source has been developed. The shunting arc plasma is generated around a carbon rod with a diameter of 2 mm and a length of 40 mm bridged between electrodes. The plasma is driven by the magnetic field generated by the arc current itself. The peak arc current with a sinusoidal waveform is 1.7 kA at a 20 μF capacitor charging voltage of 1 kV. The plasma was accelerated along the rail with average velocity of 4 km/sec in pressure range from 0.054 to 1.4 Pa, and went out towards a target set at 40 mm apart from the muzzle. The deposition rate of a carbon film was obtained to 100 nm for a process time of 1 min. The carbon film was in an amorphous state and a typical Raman spectrum with the D and G band was observed.

Generation of magnetically driven shunting arc discharge and amorphous carbon film preparation

Summary form only given. The shunting arc discharge is an alternating capacitor discharge through a rod of metal or semi-metal. An optimization of the discharge condition has realized the self-ignition of the arc discharge at a low input power to the rod, leading to a much longer lifetime of the rod compared with the conventional shunting arc and the peripheral arc. The shunting-arc-produced plasma mainly consists of metal or semi-metal ions, and it has also been demonstrated that the ions can be extracted from the plasma. Thus, the shunting arc can be used as pulsed ion sources of metal and semi-metal for plasma-based ion implantation and deposition (PBII&D). Amorphous carbon films were deposited at a deposition rate of approximately 1 nm/min using omnidirectional shunting arcs. In order to improve the deposition rate, the arc was driven towards the substrate using a Lorentz force arisen from the interaction between the self magnetic field and the arc current. The deposition rate was improved by a factor of approximately 100 compared with the omnidirectional case. The sinusoidal half-cycle current has a peak of 1500 A and a duration of 20 /spl mu/s at 20 /spl mu/F-capacitor charging voltage of 600 V. The driving speed of the magnetically driven speed is about 1.3 mm//spl mu/s. The arc characteristics are analyzed using the Lorentz force. From the equation of motion, the plasma density of the shunting arc is estimated to be an order of 10/sup 17/ m/sup -3/. In PBII&D experiment, the ions are extracted from the magnetically driven shunting arc discharge. In comparison with the ion current characteristics between magnetically driven and omnidirectional shunting arcs, dominant species for the carbon film deposition by magnetically driven shunting arc discharges, are carbon neutrals emitted from the carbon holders and electrodes during the plasma acceleration.

Amorphous carbon film preparation by shunting arc discharge in vacuum

Diamond-like carbon film (DLC) was deposited by PBII&D method using a carbon shunting arc discharge in vacuum. The prepared film was in a state of amorphous and its surface is clean and smooth. A pulse or DC voltage of 0 to -15 kV is applied to the substrate with any filtering method to eliminate droplets. A future prospect of the various film preparations using the shunting arc discharge was also discussed.