Thin Films Technology Lecture 3: Physical Vapor Deposition PVD Jari Koskinen Aalto University Page 1
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 2
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 3
PVD Plasma Plasma Colliding electrons ionise atoms Ions and electrons accelerate in electric field collisions excite atoms de-excitation creates photons visible light 4
Glow discharge http://astro-canada.ca
Glow discharge
Glow discharge
Glow discharge
Glow discharge
Glow discharge
Glow discharge
Glow discharge
DC Plasma glow discharge and arc 13
RF Plasma glow discharge 14 http://www.spectruma.de
RF Plasma glow discharge self bias 15 M. Ohring
Self bias at electrodes 4 Sivu 16
Energetic ion surface interactions 17
PVD coating process (High) vacuum long mean free path of ions high ion energy cleaning of surface desorption of gas sputtering of surface removal of oils water oxides 18
Average mean free path (distance between collission) in nitrogen residual gas <λ> Ultra Good High High Intermediate Rough Total pressure of residual gasses
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 20
Source materials Coating material from solid target or gas http://sunnygreater.com/products/sputtering_targets 21
Energetic ion and surface interactions collision cascade 10-14 10-13 s thermal spike 10-13 10-12 s Fast diffusion fast cooling relaxation 22 Jari Koskinen, Kts. Aalto simulaatio University 2016
Sputtering yield 23
Sputter yield and sublimation energy 24
Sputter yield angle dependence and energy distribution 25
Sputter yield angle dependence and energy distribution 26
Sputter yield angle dependence and energy distribution 27
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 28
PVD (Physical Vapour Deposition) Material from solid or gas Plasma Energetic ions hit surface Ions and neutrals grow the film https:// www.youtube.co m/watch? v=lre5eqx9ofo www.iap.tuwien.ac.at/www/opt/images/parasol.jpg
PVD growth process Ion energy E i 10-1000 ev Surface temperature -190 C - 500 C (normally < 200 C) incidence angle Ion density Gas pressure Substrate surface 30 - Chemistry - Impurities - Topography
Competition of growing crystals Handbook of Deposition Technologies for Films and Coatings - Science, Applications and Technology (3rd Edition) Edited by: Martin, Peter M. 2010 William Andrew Publishing Sivu 31
Coating structure and plasma parameters slow hot fast cold 3/8/16 32
Modified Thorton diagram A. Anders, Thin Solid Films 518 (2010) 4087 4090 Sivu 33
Subplantation Sivu 34
Subplantation Sivu 35 Schematic diagram of densification by subplantation. A fraction of the incident ions penetrate the film and densify it, the remainder end up on the surface to give thickness growth.
Subplantation and experiments -Carbon Sivu 36
Subplantation Sivu 37
evolution of roughness Fig. 2. Schematic of roughness variation with film thickness in a general case. At first, the films consist of a series of islands where the new phase has nucleated, and the roughness increases quickly. Then the roughness peaks and decreases as the islands coalesce to form a closed, continuous film. The third stage consists of a constant roughness for epitaxial films. Finally, the roughness increases gradually above a roughening transition. The smoothness of tetrahedral amorphous carbon Diamond and Related Materials, Volume 14, Issues 3-7, March-July 2005, Pages 913-920 C. Casiraghi, A.C. Ferrari, J. Robertson
Stress Control Gas pressure /temperature Tensile stress due to collapsing of voids Higher temperature annealing of structure low stress Compressive stress subplantation 3/8/16 39
Compressive stress f FD = conc. of Frenkel defects f Ar = conc. of argon ΔΩ FD = volume change due to Frenkel defects ΔΩ Ar = volume change due to argon entrapped 3/8/16 40
Tensile stress 3/8/16 41
Ion beam nano roughening Enhanced adhesion 42
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 43
PVD methods PVD Sputtering Evaporation Diode Magnetron Ion beam Triode Resistive Arc Inductive e-beam Radio freq. Pulsed cathode DC sputtering Pulsed DC Balanced Unbalanced Balanced Unbalanced Filtered Non-filtered Steered Random
Ion beam sputtering Kaufman http:// www.youtube.com/ watch?v=ibcr- B258J8&NR=1
Surface coating methods more details
PVD methods
Electron beam evaporation Tyhjiöhöyrystys
Ion plating
Sputtering 50
Magnetron-sputtering Jari Koskinen, Lähde: Aalto Angstrom University Sciences, 2016 Inc.
Sputtering Principles of Sputtering animation Sputtering process, commercial Sputtering on Si wafers 52
Unballaced magnetron sputtering Magnetron-laitteisto
Closed field magnetron sputtering Magnetron-laitteisto
PVD-pinnoitin
Pulsed Plasma Diffusion
HIPIMS denser films
Reactive sputtering
Reactive sputtering
Reactive sputtering
Reactive sputtering
Reactive sputtering
Reactive sputtering
Arc discharge deposition Arc discharge video
Arc disharge cathode spot www.shm-cz.cz/files/schema01.jpg
Arc discharge process arc current concentrated into filaments arcs intense electron emission intense ion emission due to electron current ( atoms/electrons 1/100) ionization of atoms formation of plasma flow of ions to cathode intense sputtering of atoms 10 6-10 8 A/m 2 overlapping thermal spikes materials is melted and sublimated in cathode spots cathode spots move randomly or could be steered by using magnets electons ionize vapor and create more electrons increase of current ions accelerate due to potential difference in plasma due to multiple collisions with fast electrons macro particles (up to 10 µm diam.i are formed Timko, Nordlund simulations http://prb.aps.org/ supplemental/prb/v81/ i18/e184109
Filtered arc
Three types of bonding of carbon atoms sp 3 - Four string σ bonds in tetraedric directions sp 2 - Two σ bonds in plane - One weekπ bond ( non localised electron- conductivity) sp 1 - Two σ linear bonds - Two week π bonds (non localised electrons- conductivity)
Carbon structures- allotropies a diamond b graphite c lonsdalite (hex diam.) d fullerene 60C e fullerene 540C f fullerene 70C g amorphous carbon h carbon nano tube
Carbon Carbon has 3 hybridised bondings sp 3, sp 2, sp 1 sp 3 bondings form four equal carbon-carbon bonds producing tetrahedral structure of diamond Graphite has three sp 2 hybrid orbitals in plane 74
Diamond-like carbon (DLC) Various forms of C-H alloys presented in a ternary phase diagram DLC is a metastable form of amorphous carbon DLC films have a mixed sp 3 / sp 2 structure with different sp 3 and sp 2 proportions depending on deposition technique and parameters 75
76
Properties of ta-c as function of E i Sivu 77
Composition, effect to properties Composition as a function of deposition parameters, nitrogen composition (partial pressure of N2) Sivu 78
Pulsed laser deposition PLD high ionization evaporation of any material also in reactive gas stoichimetry of target to the surbstrate good control of depostion rate expensive lasers slow depostion rate not yet in industrial level http://www.youtube.com/watch_popup?v=g9rm4qhbnl0&vq=medium#t=19
E i as a function of laser pulse energy Sivu 80
Multilayer coatings TiAlN-multilayer
Ultrahard nanocomposte coatings - single layer At least two immiscible materials - nano-crystalline and amorphous Crystal growth limited by segregation of other phase in grain boundary Smaller crystal size -> higher hardness Typical: - nc-men/ nitride - nc-men/metal 82
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 83
PVD coatings - commercial TiAlN-multilayer Platit coatings Coating guide http://www.platit.com/coating Barlzers coatings http://www.oerlikon.com/balzers/com/en/coating-guideoverview/ Hauzer Techno Coating http://www.hauzertechnocoating.com/en/
DUPLEX- coating plasmanitrading + PVD-coating
Contents Plasma Ion surface interactions Film growth mechanisms Different PVD methods Commercial PVD coatings Scale up 86
Large volumes, up scaling Hear reflecting, self cleaning, photo voltaic /www. www.vonardenne.biz/
New emerging PVD methods vacuum polymer deposition (VPD) high-power pulsed magnetron sputtering (HPPMS or HIPIMS) filtered cathodic arc deposition glancing angle deposition (GLAD).