Specific Process Knowledge/Thin film deposition/Deposition of Tungsten: Difference between revisions
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<i> This page is written by <b>DTU Nanolab staff</b></i> | |||
Tungsten (W) | =Tungsten (W)= | ||
==Sputtering of 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]] | *[[/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)]] | |||
| Line 23: | Line 40: | ||
! General description | ! General description | ||
| E-beam evaporation of W | | E-beam evaporation of W | ||
| Sputtering of W | | DC Sputtering of W | ||
| Sputtering of W | | DC and HiPIMS Sputtering of W | ||
| Sputtering of W | | DC Sputtering of W | ||
|- | |- | ||
|-style="background:Lightgrey; color:black" | |-style="background:Lightgrey; color:black" | ||
| Line 31: | Line 48: | ||
|Ar ion beam | |Ar ion beam | ||
|None | |None | ||
| | |RF bias on a substrate | ||
|None | |None | ||
|- | |- | ||
| Line 40: | Line 57: | ||
|10Å to 600nm | |10Å to 600nm | ||
|10Å to 600nm | |10Å to 600nm | ||
|10Å to | |10Å to 250nm | ||
|- | |- | ||
| Line 48: | Line 65: | ||
|about 1 Å/s | |about 1 Å/s | ||
|about 1 Å/s | |about 1 Å/s | ||
| | |configuration dependent | ||
|-style="background:WhiteSmoke; color:black" | |-style="background:WhiteSmoke; color:black" | ||
! Batch size | ! Batch size | ||
| Line 60: | Line 77: | ||
*small pieces | *small pieces | ||
| | | | ||
*Up to | *Up to 10x4" wafers | ||
*Up to | *Up to 10x6" wafer | ||
*small pieces | *small pieces | ||
| | | | ||
*Up to 1x4" wafers | *Up to 1x4" wafers | ||
*small pieces | *small pieces | ||
|- | |- | ||
| Line 116: | Line 132: | ||
(for a 60 nm film it rose above 123 C) | (for a 60 nm film it rose above 123 C) | ||
Wait for low base pressure (3-5 10<sup>-7</sup> Torr) | 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 0.107 nm/s for 150W and 3mTorr (Src3, DC) | ||
|Deposition rate is 0. | |Deposition rate is 0.124 nm/s for 140W and 3mTorr (PC3, Src3 DC), | ||
|Deposition rate is 0. | |||
(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.'' | '''*''' ''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.'' | ||