1. LNL,11 -10 - 2006 E. Balsamo, M. Lacroix, A. Benardais, L.Grandsire, A. Frigo, and V. Palmieri, A. Variola Nanometric thickness TiN sputtering coating for RF windows RF windows

2. Outline: RF windows TiN characteristics and properties Methods : Reactive sputtering TiN coating physical and chemical characterization

3. RF WINDOWS Pressure and Temperature transition and allow the RF power passage low rf loss and low outgassing rate durable under heat treatment resistant to the mechanical sollicitations low rf loss and low outgassing rate durable under heat treatment resistant to the mechanical sollicitations ceramic disk in alumina ALUMINA H. Matsumoto REMARK:

4. Breakdown of Al 2 O 3 rf windows Multipactor (1-100 MW): due to the high yield of secondary electron emission takes place during rf operationMultipactor (1-100 MW): due to the high yield of secondary electron emission takes place during rf operation Flash-over phenomena (30-250 MW): considered to be an avalanche of electrons which have been trapped in mechanically introduced defects.Flash-over phenomena (30-250 MW): considered to be an avalanche of electrons which have been trapped in mechanically introduced defects. Breakdown and melting S. Michizono

5. Coating with low SEE yield as Ti, Cr 2 O 3,TiN on alumina. BUT BUT: 1) very thin films could not sufficiently reduce SEE yield 2) thick films cause excessive heating due to ohmic losses. Optimize the thickness ~10 nm A way for suppress multipactor

6. TITANIUM NITRIDE conductive conductive chemically stable chemically stable hard material hard material USES: - cutting and grinding tools as a protective film - wear surfaces - decorative - semiconductors and barrier layers - superalloys to prevent whisker growth of Al 2 O 3

7. TiN DEPOSITION TECNIQUES : Vapor deposition in ammonia pressure; Plasma Source Ion Implantation (PSII); Thermochemical Nitridation; High Velocity Oxygen Fuel Thermal Spray Process (HVOF); Metal-Organic Chemical Vapor Deposition (MOCVD); Atomic-Layer Chemical Vapor Deposition (ALCVD) using TiCl 4 and NH 3 as precursors; by the reaction of titanium sol-gel with a nitrogenous admixture under laser irradiation; Reactive Magnetron Sputtering (PVD).

8. REACTIVE SPUTTERING: θ1θ1 1-θ 1 target Area θ2θ2 1-θ 2 Chamber Area JJF F F1F1 F2F2 F3F3 F4F4 sputtering of an elemental target in presence of a gas, in our case N 2. The reaction between the two partners will form a compound Scheme of a reactive sputtering system Ar,N 2 Pump q0q0 qtqt qpqp qcqc Target Stationary state during deposition Θ 1 = fraction target of compound molecules (1- θ 1 ) = elemental non-reacted target atoms S.Berg

9. Hysteresis effect Typical experimental curve for reactive sputtering process S.Berg Deposition rate (u.a) Reactivegasflow(sccm) 1 0.2 0.4 0.6 0.8 1234 Deposition rate (a.u ) Deposition rate (a.u ) Reactivegasflow(sccm) 1 0.2 0.4 0.6 0.8 1234 Hysteresis region

10. SCOPE: Stoichiometric TiN film deposition with uniform fixed thickness on the whole surface (10 nm and 800nm) Al 2 O 3 disk (Ø 50.8 mm, thickness 3.2 mm) Al 2 O 3 cylinder (Ø 50 mm, height 60 mm) ON High purity of 99.7%

11. SPUTTERING CHAMBER Ti target (99,95 % purity) Working gas: Ar Reactive gas: N 2 10” rotating magnetron Operating parameters for deposition of TiN

12. Method 1.Determine N 2 and Ar partial pressure and distance target-substrate to obtain stoichiometric TiN; (on quarz 9 x 9 mm and sapphire 10 x 10) 2.Determine substrate position in order to obtain stoichiometric TiN on the whole surface; (on tempered glass 50 x 50 mm) 3.Good parameters control high reproducibility depositions 4.Determine deposition rate in such way to have the demanded thickness

13. Coating characterization XRD Stoichiometry: XRD SIMS Qualitative elementar analisy : SIMS profilemeter Film thickness: profilemeter ESCA Surface chemical analisy: ESCA PHYSICAL CHEMICAL

14. Stoichiometric TiN on quartzs Relationship between N 2 partial pressure and deposition results of TiN. Relationship between N 2 partial pressure and deposition results of TiN. Film colour changes from metallic grey to gold, than brown with the increasing of nitrogen partial pressure. # dep Ar (mbar) N 2 (mbar) I (A)V(V)P(kW) t dep. (min) Plasma color Film color thickness (μm) R (Å/sec) 2 1.0 ∙ 10 -2 1.2 ∙ 10 -3 45842.42fuchsiagrey-- 3 8.0 ∙ 10 -3 2.0 ∙ 10 -3 84914.030 white- green dark grey -- 4 9.5 ∙ 10 -3 2.7 ∙ 10 -3 3515325whitegold -- 6 5.8520320white light- brown 0.86.7 9 3.7525325whitebrown1.48.4 (Distance target-substrate 134 mm and distance substrate respect target axis 105 mm) 8.0 ∙ 10 -3 3.4 ∙ 10 -3 3.0 ∙ 10 -3 Increasing N 2 pressure

15. TiN XRD TiN XRD Spectrum of diffracted X ray intensity versus 2θ angle Sample 14 Counts Position 2θ (degrees)

16. Diffractometry analysis in order to optimize the stoichiometry Counts Chemical Formula Peak (211) 2Theta d-spacing TiN36.6632.44017 TiN 0,7636.7262.44508 TiN 0,6136.7742.44205 UNDER STOICHIOMETRIC FILM Dark grey film Increasing N 2 pressure

17. Counts Position 2θ (degrees) Chemical Formula Peak (211) 2Theta d-spacing TiN36.6632.44017 TiN 0,7636.7262.44508 TiN 0,6136.7742.44205 UNDER STOCHIOMETRIC FILM Diffractometry analysis in order to optimize the stoichiometry Gold film Increasing N 2 pressure

18. Chemical Formula Peak (211) 2Theta d-spacing TiN36.6632.44017 TiN 0,7636.7262.44508 TiN 0,6136.7742.44205 Diffractomety analysis in order optimize the stoichiometry Brown film STOICHIOMETRIC FILM!!! Counts

19. Influence distance target-substrate to obtain stoichyometric TiN

20. SPUTTERING RATE VS POSITION

21. In conclusion for planar sample: Process parameters: = 3.4 ∙ 10 -3 mbar = 8.0 ∙ 10 -3 mbar Position disk: 4-8 cm from the centre of the target Deposition time: 10 nm ~ 12 sec 800 nm ~ 16 min and 46 sec 9X9 mm TiN deposited quartz 45 mm ø alumina disk before deposition

22. DISK after deposition 10 nm 800 nm

23. Cylinder deposition Thickness variation vs distance from the target for vertical sample

24. Cylinder deposition Percentual thickness variation vs distance from the target for vertical sample 25% from average 2 step deposition

25. CYLINDER after deposition 800 nm 10 nm

26. ESCA RESULTS: 1) Elementary and quantitative Analyses Within the limit of sensitivity of the technique (0.1 to 0.5% At.), no other element was detected (H and He nondetectable): 12 nm 2) Chemical Formula of the detected elements Carbon : Pic C 1s Oxygèn : Pic O 1s Titanium : Pic Ti 2p3/2 Nitrogen : Pic N 1s The Ti / N stochiometric ratio is ~1 (error better than 2 %)

27.  Ti : (46,47,48,49,50) Ti +, 96 Ti 2 +  N 2 : 14 N +, 26 CN -, 62 TiN +, 110 Ti 2 N +, 124 Ti 2 N 2 +  C : 12 C +, 12 C -, 24 C 2 - 26 CN -, 38 C 2 N -, 50 C 3 N - 60 TiC +, 74 TiCN +, 108 Ti 2 C +  O 2 : 16 O +, 16 O -, 42 CNO -, 64 TiO +, 64 TiO -, 112 Ti 2 O +, 126 Ti 2 NO + SIMS RESULTS

28. Conclusions: TiN majoritaire ( + Ti x C y + Ti x’ C y’ N z’ + Ti x’’ O y’’ N z’’ ) [e ~ 1 µm] SUBSTRAT (alumine) FROM ANALYSIS ESCA AND SIMS: TiN(1-x) with x ~ 0 SUBSTRATE (alumina) TiN (+Ti x C y +Ti x’ C y’ N z’ +Ti x’’ O y’’ N z’’ ) CARBIDES, OXIDES, OXYNITRIDED AND CARBONITRIDES

29. Thanck you … for your attention

30. AND NOW … DEPOSITION ALL SAMPLES

31. Thanks for the collaboration to For any questions….

32. 2 types of SUBSTRATE : A) disk (diameter 50.8 mm, thickness 3.2 mm, high purity of 99.7%, HA997). B) cylinder (diameter 50 mm thickness 60 mm, high purity of 99.7%, HA997. ) nm thick TiN films having lower secondary electron emission coefficients so as to suppress multipactoring [2]”. How? with dc reactive sputtering2

33. RF WINDOWS ceramic disk in alumina Copper pillbox windows Isolates vacuum from a zone with different pressure and temperature and concurs the rf power passage low rf loss and low outgassing rate durable under heat treatment resistant to the mechanical sollicitations low rf loss and low outgassing rate durable under heat treatment resistant to the mechanical sollicitations

34. (Al 2 O 3 ) perchè questo materiale è trasparente alla radiazione nel campo delle microonde, resistente alle sollecitazioni meccaniche cui è soggetto e compatibile con l’ultra alto vuoto. La trasparenza alle microonde è proporzionale al grado di purezza dell’allumina: più alta è la concentrazione di elementi presenti nella ceramica, più bassa è la trasmittanza del materiale [i] (Figura 0 ‑ 2). [i] [i] H. Matsumoto “Development Of a High Power RF-Window at s-band”, 1996 International Accelerator School in Japan Figura 0 ‑ 2: Conduttività termica e perdita dielettrica per allumina di diversa purezza attraversata da radiazione elettromagnetica a 10 GHz 1. RF WINDOWS Characteristic: - formed by an ceramic disk (alumina) and a copper pillbox windows; - isolates vacuum from a zone with different pressure and temperature; - concurs the rf power passage. specific alumina ceramics material has a low outgassing rate and is durable under heat treatment, it is widely used in accelerator vacuum systems as electrical insulator

35. A 8.0 ∙ 10 -3 5.0 ∙ 10 -3 5.32566320 biancobronzati 0.81 40.6 6.8 B 0.67 33.6 5.6 C 1.04 52.0 8.7 D 0.78 39.2 6.5 E 1.09 54.4 9.1 F 1.1 55.0 9.2 G 0.67 33.7 5.6 H 0.40 19.9 3.32

36. Hysteresis effect Typical experimental curve for reactive sputtering process: the deposition rate doesn’t decrease and increase at the same value with the supply of the reactive gas. S.Berg Deposition rate (a.u) Reactive gas flow (sccm) 1 0.2 0.4 0.6 0.8 1234 Hysteresis region

37. XRD

38. Counts Position (2 θ) Chemical Formula Reference number Picco (211) 2Teta d-spacing TiN00-038-142036.6632.44017 TiN 0,7601-087-062736.7262.44508 TiN 0,6101-076-183436.7742.44205 FILM OVER STOCHIOMETRIC

39. TiN DEPOSITION TECNIQUES : HVOF; PSII; Thermochemical Nitridation; Metal-Organic Chemical Vapor Deposition (MOCVD); Atomic-Layer Chemical Vapor Deposition (ALCVD) using TiCl4 and NH3 as precursors; - considerably greater temperature range for deposition - by the reaction of titania sol-gel with a nitrogenous admixture under laser irradiation; Reactive Magnetron Sputtering (PVD).

40. PROFILOMETER Profilometer Alpha-Step 200

41. XRD The instrument

42. SIMS RESULTS principal detected elements:  Ti : (46,47,48,49,50) Ti +, 96 Ti 2 +  N 2 : 14 N +, 26 CN -, 62 TiN +, 110 Ti 2 N +, 124 Ti 2 N 2 +  C : 12 C +, 12 C -, 24 C 2 - 26 CN -, 38 C 2 N -, 50 C 3 N - 60 TiC +, 74 TiCN +, 108 Ti 2 C +  O 2 : 16 O +, 16 O -, 42 CNO -, 64 TiO +, 64 TiO -, 112 Ti 2 O +, 126 Ti 2 NO +

43. Spectrum of diffracted X ray intensity versus 2θ angle Sample 14 Counts Position (2 θ) XRD

44. Distancelattice planes 211 - position Distance lattice planes 211 - position