Speaker
Arutiun P. Ehiasarian
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I2.005.pdf
High Power Impulse Magnetron Sputtering - the Age of Adolescence
A. P. Ehiasarian,
National HIPIMS Technology Centre - UK, Materials and Engineering Research Institute,
Sheffield Hallam University, Howard St., Sheffield, S1 1WB, UK
High power impulse magnetron sputtering (HIPIMS) is one of the youngest sputtering
technologies for thin film deposition. It provides a new deposition parameter space which is
unattainable by conventional technologies and results in unique material properties.
Magnetron sputtering devices confine plasmas in an E×B field where the cathode is planar
and the magnetic field is arranged in a closed loop tunnel along the solid surface. The plasma
sputter-erodes the cathode to produce a deposition vapour.
HIPIMS is operated in a magnetron sputtering configuration but utilises a short (impulse)
quasi-stationary gas discharge with duration of ~100 µs and duty cycles of <1% reaching
high peak power densities of 3000 Wcm-2 at the cathode at voltages of several hundred volts.
Within each HIPIMS pulse the discharge is ignited through an electron ionisation wave and
then develops into a cold metal plasma. The properties of the target material such as sputter
yield, atomic mass and ionisation potential determine film growth conditions at the substrate.
The timescales are sufficient to produce dense metal plasma of 1013 cm-3 whilst avoiding
excessive heat buildup and glow-to-arc transitions on the cathode. The plasma pressure may
exceed the confinement fields causing localised rupture and intense particle emission. The
emission points organise themselves on the crests of a wave propagating in the E×B direction
whose velocity is related to the ionisation degree.
HIPIMS plasmas can induce a metal implantation zone of a few nanometres to promote
adhesion of the coating to the substrate by producing a crystalline interface and a chemical
environment for better wetting during film nucleation which result in local epitaxial growth.
At highly ionised conditions Nb films have better crystallinity and superconducting
properties. Better coverage of meshes and high aspect ratio vias is achieved.
In reactive conditions, deposition flux contains highly dissociated nitrogen which promotes
a 200 crystallographic texture and fully dense column boundaries in TiN monolithic films.
Nanolayered CrN/NbN and CrAlN/CrN developed with low roughness and enhanced
density making them suitable for biological and high-temperature oxidation environments.
Industrial uptake is rife in the fields of hard coatings and microelectronics with a number of
vendors providing turn-key solutions and products made with HIPIMS technology.
