Specific Process Knowledge/Thin film deposition/Deposition of Chromium

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Chromium deposition

Chromium can be deposited by e-beam evaporation, thermal evaporation, and sputter deposition. It should be noted that in e-beam evaporation, chromium does not melt but evaporates directly from the solid phase. In the chart below you can compare the different deposition equipment. Further down you will find the results of some studies on chromium deposition.

	E-beam evaporation (Temescal)	E-beam evaporation and sputter deposition (Wordentec)	Thermal evaporation (Thermal evaporator)	Sputter deposition (Lesker sputterer)	Sputter deposition ((Sputter-system Metal-Oxide (PC1) and Sputter-system Metal-Nitride (PC3)) )
General description	E-beam deposition of Chromium	E-beam and sputter deposition of Chromium	Thermal deposition of Chromium	Sputter deposition of Chromium	Sputter deposition of Chromium
Pre-clean	Ar ion bombardment	RF Ar clean		RF Ar clean	RF Ar clean
Layer thickness	10Å to 1µm*	10Å to 1µm*	80 nm	at least up to 200 nm	at least up to 200 nm
Deposition rate	0.5 Å/s to 10 Å/s	10 Å/s to 15 Å/s (e-beam) Sputtering: Depends on process parameters. See here and process log.	1 Å/s	Depends on process parameters. At least up to 1.48 Å/s. See process log.	Depends on process parameters.
Batch size	4x6" wafers or 3x8" wafers (ask for holder) Many smaller pieces	24x2" wafers or 6x4" wafers or 6x6" wafers	4x 2" wafer or 1x 4" wafers or 1x6" wafer or Several smaller pieces In theory up to 8" wafer (or 2x4" wafer) but uniformity will be bad	1x6" wafers Smaller pieces/wafers	up to 10x4" wafers or up to 10x6" wafers or many smaller samples
Allowed substrates	Silicon wafers Quartz wafers Pyrex wafers	Silicon wafers Quartz wafers Pyrex wafers	III-V materials Silicon wafers Quartz wafers Pyrex wafers	Silicon wafers and almost any other. Special carrier for III-V materials.	Silicon wafers And almost any that does not degas. Special carrier for III-V materials.
Allowed materials	Silicon oxide Silicon (oxy)nitride Photoresist PMMA Mylar Metals See also the cross-contamination sheet	Silicon Silicon oxide Silicon nitride Silicon (oxy)nitride Photoresist PMMA Mylar SU-8	Silicon oxide Silicon (oxy)nitride Photoresist PMMA Mylar	almost any, see cross-contamination sheet	Almost any - see cross contamination sheets for PC1 and PC3
Comment	Takes approx. 20 min to pump down	Takes approx. 1 hour to pump down	Takes approx. 20 min to pump down		Takes approx. 5 min to pump down load lock and 6 min for transfer to processing chamber

* For thicknesses above 600 nm, request permission from metal@danchip.dtu.dk to ensure there is enough material.

Studies of Cr deposition processes

Uniformity of Cr layers - Uniformity of Cr layers deposited with different methods and settings

Sputtering of Cr in Wordentec - Settings and deposition rates

Sputtering of Cr in Sputter system (Lesker) - Settings and deposition rates

Thermal evaporation of Cr in Thermal evaporator - Settings and deposition results

Stress in sputtered Cr films - Extremely high tensile stress in Cr films deposited at high temperature