Specific Process Knowledge/Thin film deposition/10-pocket e-beam evaporator

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All contents by DTU Nanolab staff

E-Beam Evaporator (10-pockets)

The 10-pocket electron-beam evaporator allows line-of-sight deposition of 10 different materials. In line-of-sight deposition only the surface of the sample facing the source directly is coated, which is useful for example for lift-off. This particular machine was purchased by Nanolab in 2023. It was made by Temescal, a company owned by FerroTec, and is very similar to the other Temescal e-beam evaporator bought by Nanolab in 2018, which we call the E-beam Evaporator (Temescal).

In both of the Temescal e-beam evaporators, one material can be deposited at a time, and you can deposit many layers one after another. Up to four 6" wafers or three 8" wafers can be loaded at a time for deposition on the surfaces facing the evaporation source, or on up to one 6" wafer can be loaded for tilted deposition. Using sample holder inserts, you can deposit on samples of different sizes and shapes. Notice that if you want to lift off layers deposited on 8" wafers you may need to adjust the lithography parameters as deposition on the edges of the substrates will at times be from angles slightly away from the perpendicular to the substrate surface. This is because, unlike the HULA (high uniformity lift-off assembly) normally used for 6" and smaller substrates, the holder for 8" wafers is not optimized for lift-off .

Some special features of the 10-pocket system compared to the other Temescal e-beam evaporator are:

sample heating up to 250 °C
low oxygen flow possible
A few nonmetals, namely silicon, silica, and alumina, are available. Please only deposit these materials in the afternoon before a scheduled service as they can cause a lot of flakes in the machine.

You need additional training to use the above special options.

The user manual, user APV, and contact information can be found in LabManager:

E Beam Evaporator (10-pockets) in LabManager

Training videos may be found here:

Training videos on Youtube

Process information

Acceptance test report with results from October 2023. Describes thickness uniformity tests, side wall deposition tests, sheet resistance tests and tests of the heater and oxygen flow.

Materials for e-beam evaporation

These materials are available in the 10-pocket e-beam evaporator:

In addition to the pure metals you are welcome to experiment with depositing their oxides by adding oxygen during growth, though we expect the resultant films to be O-poor. E.g., TiO_x films deposited with a low oxygen flow during acceptance testing had a stoichiometry of approx. TiO_1.8. Please talk to staff if you wish to work with the oxides.

Most of these materials on the list above are fixed and will be present in the machine at least a year at a time. This applies to: Al, Cr, Au, Ni, Pt, Si, Ag, and Ti.

A few of them are deposited from liners and may be exchanged on request. This applies to: Al₂O₃, Cu, Ge, and SiO₂.

If you wish to evaporate a metal that is not on this list, you should use the E-beam Evaporator (Temescal), where you can request almost any metal. For other materials you may be able to use sputtering or ALD - see the list of available materials on the Overview page.

Thickness measurement, deposition rate and process control

Read about how the machine measures the thickness of the growing film using a quartz crystal monitor, how accurately you can control the rate/thickness, and other useful information about e-beam deposition here: Thickness, rate, process control.

Particulates in the films

Read about optimizing film quality including how to minimize the number of particulates in Au films in the E-beam evaporator (Temescal).

Equipment performance and process related parameters for the 10-pocket e-beam evaporator

Purpose	Deposition of metals	E-beam evaporation of metals Line-of-sight deposition Possible to tilt sample Possible to heat samples to 250 °C Possible to add O₂ flow during growth
Performance	Film thickness	10Å - 1µm* (material dependent)
	Deposition rate	1Å/s - 10Å/s* (material dependent)
	Thickness uniformity	up to 3 % Wafer-in-Wafer, Wafer-to-Wafer and Batch-to-Batch variation **
	Thickness accuracy	May vary by up to about +/- 10 %
Process parameter range	Process Temperature	Approximately room temperature up to 250 °C. There is no controllable cooling, so substrates may get heated passively during evaporation of some metals, e.g., Au and Pt. You can see the approximate temperature from the readout of the thermocouple in the chamber.
	Process pressure	Below 110^-6 mbar before deposition starts Below 810^-6 mbar during deposition
	Source-substrate distance	69.85 cm
Substrates	Batch size	Up to four 6" wafers Or up to three 8" wafers Or up to one 6" wafer with tilt
	Substrate material allowed	Almost any that can be securely attached and will not outgas. See also the cross-contamination sheet.
	Material allowed on the substrate	Almost any material that does not outgas and where there is no risk of fragile structures dislodging and falling into the machine during the deposition. See also the cross-contamination sheet.

* See table in manual with max. allowed rate and cumulative thickness. If you would like to deposit a thicker cumulative layer of a material than the limit in the table, please request permission from metal@nanolab.dtu.dk. This is so we can ensure that enough material will be present and that the the machine can be cleaned up as needed after the deposition.

** Defined as the ratio of the standard deviation to the average of the measurement made using the DektakXT. For further details see the acceptance test.