Title :
Metal Ionization in a High-Power Pulsed Sputtering Penning Discharge
Author :
Yukimura, Ken ; Ehiasarian, Arutiun P. ; Ogiso, Hisato ; Nakano, Shizuka ; Azuma, Kingo
Author_Institution :
Sch. of Mater. Sci. & Eng., Harbin Inst. of Technol., Harbin, China
Abstract :
Droplet-free metal plasma sources are a promising technology for enhancing the adhesion of deposited films to a smooth surface. High-power pulsed sputtering (HPPS) plasma is an arc-free glow discharge plasma with an instantaneous power consumption of several tens of kilowatts, although the average power consumed is the same as that in conventional sputtering discharge systems. Sputtered metallic species are significantly ionized. The fractions of singly and doubly charged ions of argon and titanium in an HPPS plasma are studied using a time-averaged ion energy distribution function in the power-density region from 0.5 to 2.5 kW/cm2. Facile production of metallic ions is confirmed. Singly charged ions are dominant in the plasma. Argon and titanium ions together constitute more than 90% of the charged particles in the plasma. The metal ions are produced with increasing plasma power consumption. The instantaneous power contributes to the ionization of the plasma species. The gas ion energies is in a narrow range of a few electronvolts. Conversely, metallic ions is in a wider range of energy up to approximately 10 eV. It is seen from an optical emission spectrum of the HPPS plasma that metallic species are highly ionized.
Keywords :
Penning discharges; argon; glow discharges; ionisation; plasma materials processing; sputtering; titanium; Ar; Ti; arc-free glow discharge plasma; argon ion; average power; charged particles; deposited film adhesion; doubly charged ion fraction; droplet-free metal plasma sources; gas ion energies; high-power pulsed sputtering penning discharge; high-power pulsed sputtering plasma; metal ionization; metallic ion production; optical emission spectrum; plasma ionization; plasma power consumption; power-density region; singly charged ion fraction; smooth surface; sputtering discharge systems; time-averaged ion energy distribution function; titanium ion; Argon; Discharges; Ions; Metals; Plasma sources; Sputtering; Glow discharge; high-power impulse magnetron sputtering (HIPIMS); high-power pulsed sputtering (HPPS);
Journal_Title :
Plasma Science, IEEE Transactions on
DOI :
10.1109/TPS.2011.2163428