S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V....
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Transcript of S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V....
![Page 1: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/1.jpg)
S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^
Padova University, Material Science Dept
* INFN - Legnaro National Labs ^ Padua University, Science faculty, Material Science Dept
° Interuniversity Accelerator Center, New Delhi
V3Si by Thermal Diffusion of SiH4 into V
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1) Theory
2) Literature review
3)Technique choice reasons
4) Method
5) Work in progress6)
Conclusions
Multilayer films
Cosputtering
Reactive sputtering
Thermal diffusion
Nomogram
Samples caracterization
Used system
V Substrate preparation
V3Si obtainment
V3Si
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18
Tc (K)
ρn
(μΩ
cm)
Nomogram
Theory
IdealR BCS ~ 1 nΩ
At T = 4.2 K,
f = 500 MHz,
s = 4,
RBCS depends
on Δ and ρn
~ 10 μΩcm
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Thermally diffused V3Si multilayer films S. De Stefano, A Di Chiara, G. Peluso, L. Maritato*, A. Saggese* and R. Vaglio*
Naples University, *Salerno UniversityCryogenics 1985 Vol 25 April
V and Si layers sequentially deposited by Electron-beam evaporation
Tc vs Annealing T (600-900°C for 1h)
Tc measured by a 4-terminal resistive method
Literature
Tcmax = 16,2 K
Tc < 0,1 K
Annealing t = 1 h
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Preliminary results on cosputtering of V3Si films by the facing-target magnetron technique
Y. Zhang, V. Palmieri, R. Preciso, W. Venturini, Legnaro National Laboratory, ITALY
Schematic diagram of the facing-target magnetron.
V target Si target
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
13.5 14.0 14.5 15.0 15.5 16.0 16.5
sample5-9
RR
K
Superconducting transition of a V3Si sample
RR
R
Literature
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6.0
9.0
12.0
15.0
18.0
10.0 15.0 20.0 25.0 30.0Silicon content ( % at. )
800oC
500oC
Reactive sputtered V3Si films Y. Zhang, V. Palmieri, W. Venturini, R. Preciso, Legnaro National Laboratory - INFN, Italy
a bSurface of two annealed samples under SEM: Grain size, (a) 0.2m, (b) 0.5m
Before annealing
After annealing
Tc (K
)
Literature
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Thermal diffusion of V3Si filmsY. Zhang, V. Palmieri, W. Venturini, F. Stivanello, R. Preciso, Legnaro National Laboratory, ITALY
Silane pressure
Heat power Temperature
Diffuse in silane
Anneal in vacuum
1.2·10-
4mbar300W 900ºC 20h 40h
Diffusion Parameters:
2.5
3.0
3.5
4.0
4.5
14.5 15.0 15.5 16.0 16.5 17.0
Bulk Vanadium, sample No.13-2V
K
AC inductive measurement:Tc ~ 16.0K ΔTc < 0.4K
Literature
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Technique Choice Reasons
• Very simple technique (RF applications!)
V3Si by Thermal Diffusion of SiH4 into V?
• There is room to improve the film quality by higher thermal diffusion temperature or by longer annealing time in vacuum.
• Promising old results
![Page 9: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/9.jpg)
Laboratory Procedure
• Used system
• V Substrate preparation
• V3Si obtainment
• Samples caracterization
Method
![Page 10: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/10.jpg)
Vacuum System
Method
Vacuum system
Controllers
SiH4 Gas Cabinet
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Heating System
Method
Nb
V substrates
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Substrate Chemical Etching
Method
Sample Reactant mixture T (°C) t (s)
Erosion rate
![Page 13: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/13.jpg)
V Substrate: Optical Microscope
HF, HNO3, H3PO4 1:1:2
50°C, 7,8 m
HF, HNO3, H3PO4 1:1:160°C, 36,2 m
HNO3, H2O, NH4F 25:12:1
30°C, 46,5 m
HF, HNO3 1:420°C, 73,8
m
Method
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HF, HNO3, H3PO4 1:1:250°C, 7,8 m
HF, HNO3 1:420°C, 73,8 m
HF, HNO3, H3PO4 1:1:160°C, 36,2 m
HNO3, H2O, NH4F 25:12:130°C, 45,5 m
V Substrate: Profilometer
Method
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V3Si obtainment
Vacuum p ~ 10-8 mbar
V substrate heatingTo get SiH4 decomposition and
Silicon diffusion
SilanizationFilm growth
(p (SiH4) ~ 10-3-10-4 mbar)
Annealing in vacuum To get rid of hydrogen
Method
![Page 16: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/16.jpg)
SEM
Process T = 850°C, p (SiH4) = 5,0x 10-4 mbar
Silanization t = 10h Annealing t = 20h
Method
V
V3Si
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XRD
Method
Angle (2θ)
Rel
ativ
e In
tens
ity
Process T = 825°C, p (SiH4) = 5,0x 10-4 mbar
Silanization t = 10h Annealing t = 20h
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A Superconductive Transition Curve
Method
V3Si 5N: 850°C, 1,0x10-3 mbar, 10h+20h
V3Si (Tc = 15,4 K)
V (Tc = 5,0 K)
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Tc vs Process T
Method
T (°C)
Tc(°
C)
p(SiH4)=5,0 x 10-4mbar, silanization t=10h, ann t=20h
Cu Contaminations?
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• Mechanical polishing
• Chemical polishing
6 GHz Cavities
1. Spinning Technique
2. Surface Treatments
Method
![Page 21: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/21.jpg)
Mechanical Polishing
SiC
Used media:
ZrO2
Method
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Before the treatmentAfter:SiC 120h + ZrO2 96h
V 6 GHz cavity: Mechanical Polishing
Method
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V 6 GHz cavity: Chemical Polishing
Used recipe:
Method
![Page 24: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/24.jpg)
• Parameters optimization: T, t and p (SiH4)
Work in progress
• Use of the best results to coat 6 GHz V cavities to test sistematically RF properties
• Different sperimental method to prepare V3Si: multilayer obtained altermatively depositing V and Si
• Plasma used to try to avoid the presence of hydrogen
![Page 25: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/25.jpg)
Conclusions
• Thermal diffusion technique
•T, t and p(SiH4) change trying to improve V3Si films properties
• Good preliminary results: Tc ~ 15 K and Tc ~ 0,4 K
![Page 26: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/26.jpg)
Cosputtering technique: Deposition T > 500°C + sometimes annealing (800°C)
Composition (RBS, EDS): composition ratio V/Si linerly dependent on the Target Voltage Ratio
Tc: four probe DC resistivity measurement
Literature
Preliminary results on cosputtering of V3Si films by the facing-target magnetron technique
Y. Zhang, V. Palmieri, R. Preciso, W. Venturini, Legnaro National Laboratory, ITALY
![Page 27: S.M. Deambrosis*^, G. Keppel*, N. Pretto^, V. Rampazzo*, R.G. Sharma°*, F. Stivanello* and V. Palmieri*^ Padova University, Material Science Dept * INFN.](https://reader034.fdocuments.in/reader034/viewer/2022051819/55154a64550346c77d8b6313/html5/thumbnails/27.jpg)
Reactive sputtering of V-Si films by a DC facing target magnetron configuration in SiH4 atmosphere
Surface: SEMComposition: EDSSuperconducting properties: DC four probe technique
Important parameters:•T•Deposition rate•SiH4 partial pressure
Literature
Reactive sputtered V3Si films Y. Zhang, V. Palmieri, W. Venturini, R. Preciso, Legnaro National Laboratory - INFN, Italy