Generation of droplet‐free high‐power pulsed sputtering (HPPS) glow plasma with several tens of kilowatts

Abstract

A droplet free metallic plasma source is promising for enhanced adhesion of films with a smooth coating surface. This paper concerns a highly ionized metallic plasma source using a pulsed Penning discharge. A high‐power pulsed sputtering (HPPS) glow discharge plasma is generated using electric‐ and magnetic‐field interactions. The metallic species are sputtered by the energetic argon ion bombardment, followed by their ionization in as short as approximately 3 μs. The plasma source is compact in size (approximately 60 × 60 × 60 mm3) and the plasma is arc‐free. The glow plasma is generated at a gap with a length of 10 mm. The magnetic field at the gap is approximately 0.3 T. A pulsed power source with a rectangular‐shaped voltage‐output is used. Fundamental electrical and optical characteristics are obtained. The glow voltage and current are approximately –0.43 kV and 37 A at 30 μs, respectively, which corresponds to a peak power of approximately 16 kW, where the applied voltage –1.2 kV and a current limiting series resistance is 20 Ω. The consumed energy is approximately 0.41 J, which corresponds to an average power of 250 W at a repetition rate of 625 Hz. The power and energy are changed by circuit conditions. In order to increase the consumed power, the current limiting‐resistance is decreased to be 3 Ω, the peak power is increased to approximately 70 kW with a power density of 2.9 kW/cm2, where a current density is 4.5 A/cm2. The ambient gas is argon at a pressure of 2 Pa. In the emission spectra, singly‐ and doubly‐ionized titanium ions are observed, following the generation of argon ions, which shows the ionization of sputtered titanium species. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electrical characteristics of arc-free high-power pulsed sputtering glow plasma

“…As a result, all of the emission spectra are from argon and titanium related species, as observed by spectral observations. It is found that the emission intensity of singlycharged titanium ions is significant in the stationary state of the plasma [7]. Thus, it is confirmed that metallic ions are produced in HPPS glow plasma.…”

“…Temporal behaviors of the optical emission from the HPPS plasma have been already investigated [7]. As a result, all of the emission spectra are from argon and titanium related species, as observed by spectral observations.…”

Voltage–current characteristics of a high-power pulsed sputtering (HPPS) glow discharge and plasma density estimation

“…A magnetic field was perpendicular to the targets, and its strength was approximately 0.3 T. In total, six permanent magnets were set behind the targets. The plasma source was set on the bottom of the vacuum chamber via a ceramic insulator with a height of approximately 80 mm [4,5].…”

“…We have also proposed a metallic plasma source using Penning discharge [3]. This is called high-power pulsed sputtering (HPPS) glow plasma [4,5]. The plasma source is compact in size, having similar power, current density and plasma density specifications to those typically seen in HIPIMS glow plasmas.…”

Temporal and spatial distributions of carbon shunting arc plasma

“…Plasma sources of a pulsed sputtering Penning discharge and an inductively coupled impulse sputtering (ICIS) glow have also been developed. 20,21) The former has an electric field parallel to the magnetic field and is compact in size. The latter requires no magnetic field to sputter metallic species from a target using a high-density ICP source.…”