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<i> This page is written by <b>DTU Nanolab staff</b></i>


=Tungsten (W)=
Tungsten (W) is a refractory metal with the highest melting point of any element, remarkable density, hardness, and outstanding resistance to radiation and corrosion, making it indispensable in semiconductor, optical, and harsh‑environment technologies.
Thin films are produced primarily by magnetron sputtering or e-beam evaporation, yielding dense, low-resistivity body-centered-cubic α-W when pressure, substrate temperature, and energy are adequately controlled.
Within semiconductor process flows, α‑W serves as a robust diffusion‑barrier/liner, gate or contact metal, and reliable via/plug fill for logic, memory, and power devices operating at elevated temperatures.
In optics, the metal’s high atomic number and thermal stability underpin multilayer W/Si or W/C stacks used in X‑ray mirrors—such as Göbel mirrors, Kirkpatrick–Baez optics, synchrotron beamline monochromators, and space‑borne telescope coatings—delivering high reflectivity and power‑handling in the soft-to-hard-X-ray range.
α‑W also supports high‑temperature plasmonic and thermally emissive coatings, mid‑IR absorbers, and durable metamaterial surfaces that endure far greater power densities than noble metals.
Beyond electronics and photonics, tungsten’s mechanical strength and radiation tolerance enable MEMS springs, X‑ray/EUV shielding, high‑temperature sensors, and dense protective components; moreover, α‑W becomes superconducting at millikelvin temperatures, allowing niche low‑loss microwave resonators and detector elements where extreme stability is required.
== Tungsten deposition ==
Tungsten (W) can be deposited by e-beam evaporation and sputtering. However, in the case of evaporation, the process generates a lot of heat, so it is not easy to deposit films much thicker than 50-60 nm. Sputtering can be used without any particular issues. In the chart below, you can compare the deposition equipment.
===Evaporation of W===
*[[/Evaporation of W in Temescal|E-beam evaporation of Tungsten in the Temescal]]
===Sputtering of W===
*[[/Sputtering of W in Sputter Coater 3|Sputtering of Tungsten in the Sputter Coater 3]]
*[[/DC Sputtering of W in Sputter-System (Lesker)|DC Sputtering of Tungsten in the Sputter-System (Lesker)]]
*[[/DC Sputtering of W in Sputter-system Metal-Nitride (PC3)|DC Sputtering of Tungsten in the Sputter-system Metal-Nitride (PC3)]]
*[[/HiPIMS Sputtering of W in Sputter-system Metal-Nitride (PC3)|HiPIMS Sputtering of Tungsten in the Sputter-system Metal-Nitride (PC3)]]


Tungsten (W) can be deposited by e-beam evaporation. In the chart below you can compare the different deposition equipment.




{| border="1" cellspacing="0" cellpadding="4"  
{| border="1" cellspacing="0" cellpadding="4"  
!  
|-style="background:silver; color:black"
! E-beam evaporation ([[Specific Process Knowledge/Thin film deposition/Alcatel|Alcatel]])
!
! E-beam evaporation ([[Specific Process Knowledge/Thin film deposition/Temescal|Temescal]])
! Sputter-system ([[Specific Process Knowledge/Thin film deposition/Lesker|Lesker]])
! Sputter deposition ([[Specific_Process_Knowledge/Thin_film_deposition/Cluster-based_multi-chamber_high_vacuum_sputtering_deposition_system|(Sputter-system Metal-Oxide (PC1) and Sputter-system Metal-Nitride (PC3)) ]])
! Sputter coater [[Specific Process Knowledge/Thin film deposition/Sputter coater#Sputter coater 03|(Sputter coater 03)]]
|-  
|-  
| Batch size
|-style="background:WhiteSmoke; color:black"
|
! General description
*Up to 1x4" wafers
| E-beam evaporation of W
*smaller pieces
| DC Sputtering of W
| DC and HiPIMS Sputtering of W
| DC Sputtering of W
|-
|-
| Pre-clean
|-style="background:Lightgrey; color:black"
|RF Ar clean
! Pre-clean
|Ar ion beam
|None
|RF bias on a substrate
|None
|-
|-
| Layer thickness
 
|10Å to 1µm
|-style="background:WhiteSmoke; color:black"
! Layer thickness
|10Å to 20nm*
|10Å to 600nm
|10Å to 600nm
|10Å to 250nm
|-
|-
| Deposition rate
 
|2Å/s to 15Å/s
|-style="background:Lightgrey; color:black"
! Deposition rate
|0.5 Å/s to 1 Å/s
|about 1 Å/s
|about 1 Å/s
|configuration dependent
|-style="background:WhiteSmoke; color:black"
! Batch size
|
*Up to 4x6" wafers
*Up to 3x8" wafers (ask for holder)
*small pieces
|
*Up to 1x4" wafers
*Up to 1x6" wafer
*small pieces
|
*Up to 10x4" wafers
*Up to 10x6" wafer
*small pieces
|
*Up to 1x4" wafers
*small pieces
|-
|-
|-style="background:Lightgrey; color:black"
! Allowed materials
|
* Silicon
* Silicon oxide
* Silicon (oxy)nitride
* Photoresist
* PMMA
* Mylar
* SU-8
* Metals
|
* Silicon
* Silicon oxide
* Silicon (oxy)nitride
* Photoresist
* PMMA
* Mylar
* SU-8
* Metals
|
* Silicon
* Silicon oxide
* Silicon (oxy)nitride
* Photoresist
* PMMA
* Mylar
* SU-8
* Metals
|
* Silicon
* Silicon oxide
* Silicon (oxy)nitride
* Photoresist
* PMMA
* Mylar
* SU-8
* Metals
|-style="background:WhiteSmoke; color:black"
! Comments
| Substrate gets hot during deposition
(for a 60 nm film it rose above 123 C)
Wait for low base pressure before start (3-5 10<sup>-7</sup> Torr)
|Deposition rate is 0.107 nm/s for 150W and 3mTorr (Src3, DC)
|Deposition rate is 0.124 nm/s for 140W and 3mTorr (PC3, Src3 DC),
(0.04 nm/s using HiPIMS - PC3, Src3)
|Note! Bad uniformity.
Deposition rate is 0.03 nm/s using big glass chamber.
Deposition rate is 0.2-0.9 nm/s (current dependent) using small glass chamber.
|}
|}
'''*''' ''For thicknesses above 20 nm talk to staff (write to thinfilm@nanolab.dtu.dk), as the heat and subsequent pressure rise means the deposition needs to be carried out in steps.''
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