Plasma Characterization & Thin Film Growth and Analysis in Highly Ionized Magnetron Sputtering
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
The present thesis addresses two research areas related to film growth in a highly ionized magnetron sputtering system: plasma characterization, and thin film growth and analysis. The deposition technique used is called high power pulsed magnetron sputtering (HPPMS). Characteristic for this technique are high energy pulses (a few Joules) of length 50-100 µs that are applied to the target (cathode) with a duty time of less than 1 % of the total pulse time. This results in a high electron density in the discharge (>1x1019 m-3) and leads to an increase of the ionization fraction of the sputtered material reaching up to 70 % for Cu.
In this work the spatial and temporal evolution of the plasma parameters, including the electron energy distribution function (EEDF), the electron density and the electron temperature are determined using electrostatic Langmuir probes. Electron temperature measurements reveal a low effective temperature of 2-3 eV. The degree of ionization in the HPPMS discharge is explained in light of the self-sputtering yield of the target material. A simple model is therefore provided in order to compare the sputtering yield in HPPMS and that in dc magnetron sputtering (dcMS) for the same average power.
Thin Ta films are grown using HPPMS and dcMS and their properties are studied. It is shown that enhanced microstructure and morphology of the deposited films is achieved by HPPMS. The Ta films are also deposited at a number of substrate inclination angles ranging from 0o (i.e., facing the target surface) up to 180 o (i.e., facing away from the target). Deposition rate measurements performed at all inclination angles for both techniques, reveal that growth made using HPPMS resulted in an improved film thickness at higher inclination. Furthermore, the high ionization of the Ta atoms in HPPMS discharge is found to allow for phase tailoring of the deposited films at all inclination angles by applying a bias voltage to the substrate. Finally, highly ionized magnetron sputtering of a compound MAX-phase material (Ti3SiC2) is performed, demonstrating that the HPPMS discharge could also be used to tailor the composition of the growing Ti-Si-C films.
Place, publisher, year, edition, pages
Institutionen för fysik, kemi och biologi , 2005.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 948
Highly ionized pulsed magnetron sputtering, HPPMS, HPPIMS, thin film, plasma analysis, Langmuir probe
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-4147ISBN: 91-85299-40-5OAI: oai:DiVA.org:liu-4147DiVA: diva2:20537
2005-06-03, 10:15 (English)
On the day of the public defence of the doctoral thesis, the status of articles III and IV was Submitted. The titles of papers VI and VII changed between their manuscript forms and when they were published.2005-10-252005-10-252013-10-30
List of papers