AVS 53rd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS2-FrM

Paper PS2-FrM9
The Ion Energy Distributions in a High Power Impulse Magnetron Discharge

Friday, November 17, 2006, 10:40 am, Room 2011

Session: Diagnostics
Presenter: J. Bohlmark, Chemfilt Ionsputtering AB, Sweden
Authors: J. Bohlmark, Chemfilt Ionsputtering AB, Sweden
M. Lattemann, Linköping Univ., Sweden
J.T. Gudmundsson, Univ. of Iceland, Iceland
A.P. Ehiasarian, Sheffield Hallam Univ., UK
Y.A. Gonzalvo, Hiden Analytical Ltd., UK
J. Carlsson, Chemfilt Ionsputtering AB, Sweden
N. Brenning, Royal Institute of Tech., Sweden
D. Lundin, Linköping Univ., Sweden
U. Helmersson, Linköping Univ., Sweden
Correspondent: Click to Email
We report on the ion energy distributions of sputtered and ionized Ti and the sputtering gas (Ar and N2) for a high power impulse magnetron sputtering (HIPIMS) discharge. High power pulses were applied to a conventional planar circular magnetron Ti target. The peak power on the target surface was 1-2 kW/cm@super 2@ with a duty factor of about 0.5 %. Time resolved, and time averaged ion energy distributions were recorded with an energy resolving quadrupole mass spectrometer. The ion energy distributions are very broad during the active phase of the discharge with maximum detected energy of 100 eV, but quickly narrows as the pulse is switched off. The time averaged measurements show that about 50 % of the Ti ions have energies over 20 eV. The broad nature of the distributions together with the fact that the Ti and gas ion distributions peak at different energies during the active phase of the discharge excludes acceleration between the plasma potential and the grounded spectrometer as explanation for the energetic ions. Instead we suggest that the shape of the distributions can be explained by a combination of a strong pressure increase in front of the target and ion acceleration by electric field instabilities. The composition of the ion flux was also determined, and reveals a high metal fraction. During the most intense moment of the discharge, the ionic flux consisted of approximately 50 % Ti1+, 24 % Ti2+, 23 % Ar1+, and 3 % Ar2+ ions. We are planning to continue the study by investigating the effect of the energetic plasma on thin film growth. It is expected that HIPIMS can be used as a tool for film densification where a substrate bias is not easily applied, which opens up for improved device or component performances.