The high purity EM-Tec sputter targets are compatible with a wide variety of desk top sputter coaters. The sputter coaters are used to sputter a very thin layer of conductive metal on non-conductive sample in order to investigate these samples with a scanning electron microscope (SEM). The EM-Tec sputter targets are compatible with the following sputter coaters, ion beam coaters or cryo-SEM preparation systems brands: Agar, Anatech/Technics, Bal-Tec, Bio-Rad, Cressington, Denton, Edwards, Emitech, EMS, Emscope, Fisons, Gatan, Hummer, ISI, JEOL, Leica, Polaron, Quorum, Safematic, SPI, Thermo and VG Microtech. Targets are relatively expensive due to the high purity of the precious metals which require multiple refining steps. A purity of 99.99% or close is desired to avoid any artefacts either in imaging or with EDX analysis. The target material you are using because it is installed in the sputter coater might not be best choice and there are alternatives for many applications.
EM-Tec Disc Type Sputter Targets
The EM-Tec disc type sputter targets are made using high purity metal foils and are available in 60, 58, 57, 54, 50, 24 and 19mm diameter. Disc type sputter targets are widely used is all brands of sputter coaters. Most modern sputter coaters use a clamping ring to hold the target. Some older systems use a target support plate where the target needs to be bonded with the target plate by using silver paint or Indium. Use the EM-Tec Disc Sputter Target Selection Table to determine the target size for your coater (alternatively measure the target in your sputter coater) or go directly to ordering information for the target size:
- Ø60mm disc type high purity EM-Tec sputter targets for sputter coaters
- Ø57mm disc type high purity EM-Tec sputter targets for sputter coatersr
- Ø54mm disc type high purity EM-Tec sputter targets for sputter coaters
- Ø50mm disc type high purity EM-Tec sputter targets for sputter coaters
- Ø24mm disc type high purity EM-Tec sputter targets for cryo-SEM preparation systems
- Ø19mm disc type high purity EM-Tec sputter targets for Gatan ion beam sputter coaters
- Ø60mm high purity EM-Tec sputter targets on target holder for Emitech and EMS sputter coaters
- Ø58mm high purity EM-Tec sputter targets on target holder for Emscope SC500 / SC500A sputter coaters
 | Ø60mm high purity EM-Tec sputter targets on target holder substrate for sputter coaters: Emitech K500X / K550X / K650X and EMS K500X / K550X / K650X |
|---|---|
| Product # | Unit |
| 70-AG6S12 | Silver Target, Ø60 x 0.3mm mounted on target holder, 99.99% Ag |
| 70-AP6S05 | Gold / Palladium Target, Ø60 x 0.1mm mounted on target holder, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AU6S04 | Gold Target, Ø60 x 0.1mm mounted on target holder, 99.99% Au |
| 70-PD6S04 | Palladium Target, Ø60 x 0.1mm mounted on target holder, 99.99% Pd |
| 70-PT6S04 | Platinum Target, Ø60 x 0.1mm mounted on target holder, 99.99% Pt |
 | Ø60mm disc type high purity EM-Tec sputter targets for sputter coaters: Denton Desk II / III / IV /V, Edwards 150B / Scancoat and Emscope SC500. |
|---|---|
| Product # | Unit |
| 70-AG6010 | Silver Target, Ø60 x 0.25mm Disc, 99.97% Ag |
| 70-AL6010 | Aluminium Target, Ø60 x 0.25mm Disc, 99.999% Al |
| 70-AP6004 | Gold/Palladium Target, Ø60 x 0.1mm Disc, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AP6005 | Gold/Palladium Target, Ø60 x 0.1mm Disc, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AP6008 | Gold/Palladium Target, Ø60 x 0.2mm Disc, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AP6009 | Gold/Palladium Target, Ø60 x 0.2mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AU6004 | Gold Target, Ø60 x 0.1mm Disc, 99.99% Au |
| 70-AU6008 | Gold Target, Ø60 x 0.2mm Disc, 99.99% Au |
| 70-CR6020 | Chromium Target, Ø60 x 0.5mm Disc, 99.95% Cr |
| 70-CU6010 | Copper target, Ø60 x 0.25mm Disc, 99.99% Cu |
| 70-IR6012 | Iridium Target, Ø60 x 0.3mm Disc, 99.99% Ir |
| 70-NI6003 | Nickel Target, Ø60 x 0.075mm Disc, 99.98% Ni |
| 70-PD6004 | Palladium Target, Ø60 x 0.1mm Disc, 99.99% Pd |
| 70-PD6008 | Palladium Target, Ø60 x 0.2mm Disc, 99.99% Pd |
| 70-PP6004 | Platinum/Palladium Target, Ø60 x 0.1mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PP6008 | Platinum/Palladium Target, Ø60 x 0.2mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PT6004 | Platinum Target, Ø60 x 0.1mm Disc, 99.99% Pt |
| 70-PT6008 | Platinum Target, Ø60 x 0.2mm Disc, 99.99% Pt |
| 70-TI6010 | Titanium Target, Ø60 x 0.25mm Disc, 99.6+% Ti |
 | Ø58mm high purity EM-Tec sputter targets on target holder substrate for sputter coaters: Emscope / Bio-Rad / Thermo VG sputter coater SC500/500A |
|---|---|
| Product # | Unit |
| 70-AG5S12 | Silver Target, Ø58 x 0.3mm mounted on target holder, 99.99% Ag |
| 70-AP5S05 | Gold / Palladium Target, Ø58 x 0.1mm mounted on target holder, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AU5S04 | Gold Target, Ø58 x 0.1mm mounted on target holder, 99.99% Au |
| 70-PD5S04 | Palladium Target, Ø58 x 0.1mm mounted on target holder, 99.99% Pd |
| 70-PT5S04 | Platinum Target, Ø58 x 0.1mm mounted on target holder, 99.99% Pt |
| Ø57mm disc type high purity EM-Tec sputter targets for sputter coaters: Agar Manual / Auto, Cressington 108 / 108auto / 108autoSE / 208HR, Emitech SC7620 / SC7610, ISI 5400, JEOL JFC 1200 / 1300 / 1400 / 1600 / 2300HR / JEC-3000FC, HoYeon HC21, Pelco SC4 / SC5 / SC6 /SC7, Polaron 5000 / 5200 / 5400 / 5800, Quorum Q150 / Q300 / SC7620 and SPI Module. |
|---|---|
| Product # | Unit |
| 70-AG5710 | Silver Target, Ø57 x 0.25mm Disc, 99.97% Ag |
| 70-AL5710 | Aluminium Target, Ø57 x 0.25mm Disc, 99.999% Al |
| 70-AP5704 | Gold/Palladium Target, Ø57 x 0.1mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5705 | Gold/Palladium Target, Ø57 x 0.1mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AP5708 | Gold/Palladium Target, Ø57 x 0.2mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5709 | Gold/Palladium Target, Ø57 x 0.2mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AU5704 | Gold Target, Ø57 x 0.1mm Disc, 99.99% Au |
| 70-AU5708 | Gold Target, Ø57 x 0.2mm Disc, 99.99% Au |
| 70-AU5712 | Gold Target, Ø57 x 0.3mm Disc, 99.99% Au |
| 70-AU5716 | Gold Target, Ø57 x 0.4mm Disc, 99.99% Au |
| 70-CO5704 | Cobalt Target, Ø57 x 0.1mm Disc, 99.99% Cr |
| 70-CO5720 | Cobalt Target, Ø57 x 0.5mm Disc, 99.99% Co |
| 70-CR5720 | Chromium Target, Ø57 x 0.5mm Disc, 99.95% Cr |
| 70-CR5799 | Chromium Target, Ø57 x 3.2mm Disc, 99.95% Cr |
| 70-CU5710 | Copper Target, Ø57 x 0.25mm Disc, 99.99% Cu |
| 70-FE5704 | Iron Target, Ø57 x 0.1mm, 99.5% Fe |
| 70-IN5708 | Indium Target, Ø57 x 0.20mm Disc, 99.99% In |
| 70-IN5720 | Indium Target, Ø57 x 0.5mm Disc, 99.99% In |
| 70-IR5712 | Iridium Target, Ø57 x 0.3mm Disc, 99.99% Ir |
| 70-IT7099 | ITO (Indium Tin Oxide) Target Ø57 x 3.0mm Disc, including 1mm thick copper backing plate, 90/10 Wt% In2O3/SnO2, 99.99% |
| 70-MG5704 | Magnesium Target, Ø57 x 0.10mm Disc, 99.99% Mg |
| 70-MO5710 | Molydenum Target, Ø57 x 0.25mm Disc, 99.95% Mo |
| 70-NB5710 | Niobium Target, Ø57 x 0.25mm Disc, 99.95% Nb |
| 70-NI5703 | Nickel Target, Ø57 x 0.075mm, 99.98% Ni |
| 70-PD5704 | Palladium Target, Ø57 x 0.1mm Disc, 99.99% Pd |
| 70-PD5708 | Palladium Target, Ø57 x 0.2mm Disc, 99.99% Pd |
| 70-PP5704 | Platinum/Palladium Target, Ø57 x 0.1mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PP5708 | Platinum/Palladium Target, Ø57 x 0.2mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PT5704 | Platinum Target, Ø57 x 0.1mm Disc, 99.99% Pt |
| 70-PT5708 | Platinum Target, Ø57 x 0.2mm Disc, 99.99% Pt |
| 70-SN5708 | Tin Target, Ø57 x 0.20mm Disc, 99.99% Sn |
| 70-TA5710 | Tantalum Target, Ø57 x 0.25mm Disc, 99.95% Ta |
| 70-TI5710 | Titanium Target, Ø57 x 0.25mm Disc, 99.6+% Ti |
| 70-WO5710 | Tungsten Target, Ø57 x 0.25mm Disc, 99.95% W |
| 70-ZN5708 | Zinc Target, Ø57 x 0.20mm Disc, 99.5% Zn |
| 70-ZN5720 | Zinc Target, Ø57 x 0.5mm Disc, 99.5% Zn |
| Ø54mm disc type high purity EM-Tec sputter targets for sputter coaters Bal-Tec SCD005 / 040 / 050 / 500 / MED10 / MED20, Emitech K575X / K575XD / K675X / K675XD, HHV BT150 / BT300, LEICA EM SCD 005 / 050 / 500 / MED20 / ACE200 / ACE600 and Safe-Matic CCU-010 |
|---|---|
| Product # | Unit |
| 70-AG5410 | Silver Target, Ø50 x 0.25mm Disc, 99.97% Ag |
| 70-AL5410 | Aluminium Target, Ø50 x 0.25mm Disc, 99.999% Al |
| 70-AP5404 | Gold/Palladium Target, Ø50 x 0.1mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5405 | Gold/Palladium Target, Ø50 x 0.1mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AP5408 | Gold/Palladium Target, Ø50 x 0.2mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5409 | Gold/Palladium Target, Ø50 x 0.2mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AU5404 | Gold Target, Ø50 x 0.1mm Disc, 99.99% Au |
| 70-AU5408 | Gold Target, Ø50 x 0.2mm Disc, 99.99% Au |
| 70-AU5412 | Gold Target, Ø50 x 0.3mm Disc, 99.99% Au |
| 70-CO5404 | Cobalt Target, Ø50 x 0.1mm Disc, 99.99% Cr |
| 70-CO5420 | Cobalt Target, Ø50 x 0.5mm Disc, 99.99% Co |
| 70-CR5420 | Chromium Target, Ø50 x 0.5mm Disc, 99.95% Cr |
| 70-CU5410 | Copper Target, Ø50 x 0.25mm Disc, 99.99% Cu |
| 70-FE5404 | Iron Target, Ø50 x 0.1mm, 99.5% Fe |
| 70-IN5408 | Indium Target, Ø50 x 0.20mm Disc, 99.99% In |
| 70-IN5420 | Indium Target, Ø50 x 0.5mm Disc, 99.99% In |
| 70-IR5412 | Iridium Target, Ø50 x 0.3mm Disc, 99.99% Ir |
| 70-MG5404 | Magnesium Target, Ø50 x 0.10mm Disc, 99.99% Mg |
| 70-MO5410 | Molydenum Target, Ø50 x 0.25mm Disc, 99.95% Mo |
| 70-NB5410 | Niobium Target, Ø50 x 0.25mm Disc, 99.95% Nb |
| 70-NI5403 | Nickel Target, Ø50 x 0.075mm, 99.98% Ni |
| 70-PD5404 | Palladium Target, Ø50 x 0.1mm Disc, 99.99% Pd |
| 70-PD5408 | Palladium Target, Ø50 x 0.2mm Disc, 99.99% Pd |
| 70-PP5404 | Platinum/Palladium Target, Ø50 x 0.1mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PP5408 | Platinum/Palladium Target, Ø50 x 0.2mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PT5404 | Platinum Target, Ø50 x 0.1mm Disc, 99.99% Pt |
| 70-PT5408 | Platinum Target, Ø50 x 0.2mm Disc, 99.99% Pt |
| 70-SN5408 | Tin Target, Ø50 x 0.20mm Disc, 99.99% Sn |
| 70-TA5410 | Tantalum Target, Ø50 x 0.25mm Disc, 99.95% Ta |
| 70-TI5410 | Titanium Target, Ø50 x 0.25mm Disc, 99.6+% Ti |
| 70-WO5410 | Tungsten Target, Ø50 x 0.25mm Disc, 99.95% W |
| 70-ZN5408 | Zinc Target, Ø50 x 0.20mm Disc, 99.5% Zn |
| Ø50mm disc type high purity EM-Tec sputter targets for sputter coaters: Anatech/Technics Hummer I / II /III, Fullam EffaCoater / EMS-76, SEC MCM-100 / MCM-200 and SPI Super |
|---|---|
| Product # | Unit |
| 70-AG5010 | Silver Target, Ø50 x 0.25mm Disc, 99.97% Ag |
| 70-AL5010 | Aluminium Target, Ø50 x 0.25mm Disc, 99.999% Al |
| 70-AP5004 | Gold/Palladium Target, Ø50 x 0.1mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5005 | Gold/Palladium Target, Ø50 x 0.1mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AP5008 | Gold/Palladium Target, Ø50 x 0.2mm Disc, 60/40 Au/Pd, 99.99% Au/Pd |
| 70-AP5009 | Gold/Palladium Target, Ø50 x 0.2mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AU5004 | Gold Target, Ø50 x 0.1mm Disc, 99.99% Au |
| 70-AU5008 | Gold Target, Ø50 x 0.2mm Disc, 99.99% Au |
| 70-CU5010 | Copper Target, Ø50 x 0.25mm Disc, 99.99% Cu |
| 70-NI5003 | Nickel Target, Ø50 x 0.075mm, 99.98% Ni |
| 70-PD5004 | Palladium Target, Ø50 x 0.1mm Disc, 99.99% Pd |
| 70-PP5004 | Platinum/Palladium Target, Ø50 x 0.1mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PP5008 | Platinum/Palladium Target, Ø50 x 0.2mm Disc, 80/20 Pt/Pd 99.99% Pt/Pd |
| 70-PT5004 | Platinum Target, Ø50 x 0.1mm Disc, 99.99% Pt |
| 70-PT5008 | Platinum Target, Ø50 x 0.2mm Disc, 99.99% Pt |
| 70-TI5010 | Titanium Target, Ø50 x 0.25mm Disc, 99.6+% Ti |
| Ø24mm disc type high purity EM-Tec sputter targets for cryo-SEM preparation systems Bio-Rad E7400 / LT7400, Quorum PP2000 / PP2000T, PP3000T / PP3010T and VG MicroTech / Fisons / Thermo models PP2200 / PP2000T |
|---|---|
| Product # | Unit |
| 70-AP2409 | Gold/Palladium Target, Ø24 x 0.2mm Disc, 80/20 Au/Pd, 99.99% Au/Pd |
| 70-AU2408 | Gold Target, Ø24 x 0.2mm Disc, 99.99% Au |
| 70-CR2412 | Chromium Target, Ø24 x 0.3mm Disc, 99.95% Cr |
| 70-IR2412 | Iridium Target, Ø24 x 0.3mm Disc, 99.99% Ir |
| 70-PT2408 | Platinum Target, Ø24 x 0.2mm Disc, 99.99% Pt |
| 70-WO2412 | Tungsten Target, Ø24 x 0.3mm Disc, 99.95% W |
| Ø19mm disc type high purity EM-Tec sputter targets for ion beam sputter coaters: Gatan Models 681 / 682 PECS and Gatan 685 PECS II |
|---|---|
| Product # | Unit |
| 70-AG1960 | Silver Target, Ø19 x 1.5mm Disc, 99.99% Ag |
| 70-AL1960 | Aluminium Target, Ø19 x 1.5mm Disc, 99.999% Al |
| 70-AP1960 | Gold/Palladium Target, Ø19 x 1.5mm Disc, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AP1965 | Gold/Palladium Target, Ø19 x 1.5mm Disc, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AU1960 | Gold Target, Ø19 x 1.5mm Disc, 99.99% Au |
| 70-CC1960 | Carbon (Graphite) Target, Ø19 x 1.5mm Disc, 99.99% C |
| 70-CR1960 | Chromium Target, Ø19 x 1.5mm Disc, 99.95% Cr |
| 70-CU1960 | Copper Target, Ø19 x 1.5mm Disc, 99.99% Cu |
| 70-IR1960 | Iridium Target, Ø19 x 1.5mm Disc, 99.99% Ir |
| 70-NB1960 | Niobium Target, Ø19 x 1.5mm Disc, 99.95% Nb |
| 70-NI1960 | Nickel Target, Ø19 x 1.5mm Disc, 99.98% Ni |
| 70-PD1960 | Palladium Target, Ø19 x 1.5mm Disc, 99.99% Pd |
| 70-PP1960 | Platinum/Palladium Target, Ø19 x 1.5mm Disc, Pt/Pd 80/20, 99.99% Pt/Pd |
| 70-PT1960 | Platinum Target, Ø19 x 1.5mm Disc, 99.99% Pt |
| 70-TA1960 | Tantalum Target, Ø19 x 1.5mm Disc, 99.95% Ta |
| 70-WO1960 | Tungsten Target, Ø19 x 1.5mm Disc, 99.95% W |
EM-Tec Annular Type Sputter Targets
Annular sputter targets are less common than the disc type sputter targets. They are used on the older Polaron sputter coaters and on the Anatech/Technics Hummer sputter coaters. For the annular targets, the target material is attached to an aluminum support ring and they are supplied as complete assemblies. Available as targets with pure gold, gold/palladium, platinum, platinum/palladium, silver, copper and nickel. There are two sizes offered:
- Ø82mm OD x Ø60mm ID annular type high purity EM-Tec sputter targets for sputter coaters
- Ø3inch OD x Ø2inch ID annular type high purity EM-Tec sputter targets for sputter coaters
 | Ø82mm OD x Ø60mm ID annular type high purity EM-Tec sputter targets for sputter coaters: Polaron / Biorad E5100 / E5150 / E5175 /SC510 / SC515 and Polaron / Quorum SC7640 / 7680 |
|---|---|
| Product # | Unit |
| 70-AG8212 | Silver Target, Ø82 x Ø60 x 0.3mm Annular on Support Ring, 99.99% Ag |
| 70-AP8204 | Gold/Palladium Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AP8205 | Gold/Palladium Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AP8208 | Gold/Palladium Target, Ø82 x Ø60 x 0.2mm Annular on Support Ring, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AP8209 | Gold/Palladium Target, Ø82 x Ø60 x 0.2mm Annular on Support Ring, Au/Pd 80/20, 99.99% Au/Pd |
| 70-AU8204 | Gold Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, 99.99% Au |
| 70-AU8208 | Gold Target, Ø82 x Ø60 x 0.2mm Annular on Support Ring, 99.99% Au |
| 70-AU8216 | Gold Target, Ø82 x Ø60 x 0.4mm Annular on Support Ring, 99.99% Au |
| 70-CU8212 | Copper Target, Ø82 x Ø60 x 0.3mm Annular on Support Ring, 99.99% Cu |
| 70-PD8204 | Palladium Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, 99.99% Pd |
| 70-PD8208 | Palladium Target, Ø82 x Ø60 x 0.2mm Annular on Support Ring, 99.99% Pd |
| 70-PP8204 | Platinum/Palladium Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, Pt/Pd 80/20 wt%, 99.99% Pt/Pd |
| 70-PT8204 | Platinum Target, Ø82 x Ø60 x 0.1mm Annular on Support Ring, 99.99% Pt |
| 70-PT8208 | Platinum Target, Ø82 x Ø60 x 0.2mm Annular on Support Ring, 99.99% Pt |
| Ø3inch OD x Ø2inch ID annular type high purity EM-Tec sputter targets for sputter coaters: Anatech / Technics Hummer V / VI / 6.2 / 8 |
|---|---|
| Product # | Unit |
| 70-AG7612 | Silver Target, Ø3inch x Ø2inch x 0.3mm Annular on Support Ring, 99.99% Ag |
| 70-AP7604 | Gold/Palladium Target, Ø3inch x Ø2inch x 0.1mm Annular on Support Ring, Au/Pd 60/40, 99.99% Au/Pd |
| 70-AU7604 | Gold Target, Ø3inch x Ø2inch x 0.1mm Annular on Support Ring, 99.99%. Au |
| 70-CU7612 | Copper Target, Ø3inch x Ø2inch x 0.3mm Annular on Support Ring, 99.99% Cu |
| 70-PD7604 | Palladium Target, Ø3inch x Ø2inch x 0.1mm Annular on Support Ring, 99.99% Pd |
| 70-PT7604 | Platinum Target, Ø3inch x Ø2inch x 0.1mm Annular on Support Ring, 99.99% Pt |
Practical Information on Selecting a Target Material to coat SEM Samples
Selection of the optimum coating material depends on the (non-conductive) sample, the application and cost. Most SEM sputter coaters allow for a relatively easy target change. When using different coating (target) materials than Gold, the use of Argon as process gas is paramount. One should be aware that each sample material behaves differently when coated. The coating quality is obviously affected by the target material and by the interaction of the sample material and metal used for the coating. Coating the SEM sample with a (highly conductive) metal makes non-conductive SEM samples conductive. An additional benefit is that most coating materials have a higher secondary electron (SE) yield than the non conductive sample material. Coating material with lower atomic numbers is more suitable for for backscattered electron (imaging) whereas coating with higher atomic numbers is more suitable for SE imaging. Below you will find some pratical guidance information for selecting the target material. The information is only valid when using modern DC magnetron SEM sputter coaters and Argon as process gas.
If EDX analysis of the sample is needed, always choose a coating (target) material which is not present in the sample, creates overlapping peaks in the EDX spectrum or otherwise interferes with the EDX analysis.
Gold
Gold is an excellent and most widely used coating material to coat non-conductive samples for standard SEM applications. Due to the low work function it is a very efficient to coat and when using cool sputter coaters and thin layers, there is hardly any heating of the sample surface. The grain size is visible when using high magnifications on modern SEMs. Gold can be used for table top SEMs with air as process gas.
Gold/Palladium
The Au/Pd alloy (60/40) is less efficient to coat than with pure gold, which results in lower sputter rates. Au/Pd is often recommended to achieve a smaller grain size. Au/Pd gives smaller grain sizes when evaporated in high vacuum, but when used in SEM sputter coaters the difference between Au and Au/Pd is hardly visible. Less suitable for heat sensitive specimens and less suitable for EDX analysis due to the extra set of peaks for Pd.
Silver
Ag is a most suitable and low cost alternative for Au in many imaging applications for low and medium magnifications ranges. It is a widely underestimated coating material. Ag has the highest conductivity of all metals. When using EDS, Ag is an alternative for Au on many biological samples if P, Cl and S need to be analyzed. Sputtering rate is similar to Au, the SE yield is somewhat lower than for Pt, Au or Ir. The grain sizes is similar or slightly larger than Au, except for samples containing halogens which can cause coarser grains. The Ag coating can tarnish (in the presence of halogens) and are less suitable for long term storage. Excellent low cost coating material for many less demanding imaging applications and table top SEMs.
An additional advantage is that the Ag coating can be dissolved and the sample surface can be studied in the original conditions. Removal of Au, Au/Pd, Pt and Ir coatings is more difficult and involves very harsh chemicals. The Ag coating can be removed with Farmer’s reducer (Mixture of Potassium Ferricyanide and Sodium Thiosulfate).
Platinum
Pt has a finer grain size than Au or Au/Pd and is therefore more suitable for higher magnifications. Excellent SE yield. The higher work function results in slower sputtering than Au. Pt tends to be sensitive for “stress cracking” when oxygen is present (oxygen can come from porous samples). More expensive than Au due to higher fabrication costs.
Platinum/Palladium
Pt/Pd alloy (80/20) has a similar grain size and SE yield as pure Pt, but is less senstive to “stress cracking”. Suitable all-round coating material for FESEM applications when thin coatings are used. Best results are achieved when using high resolution sputter coaters
Iridium
Ir exhibits a very fine grain size on virtually all materials and is an excellent all-round fine grain coating material for FESEM applications. It is the material of choice for high and ultra-high resolution FESEM imaging. With the added benefit of being a non-oxidising material and a high SE yield, it is replacing Chromium for high resolution sample coating. It requires the use of a high resolution sputter coater and has lower sputtering rates. The targets are thicker due to fabricated constraints, but overall costs are lower than for Pt or Pt/Pd. Ir is also an excellent alternative material for coating samples which have to be analyzed for carbon by EDX or WDX. A thin layer is enough to creat excellent conductivity and since the material is very rare it hardly interferes with EDX or WDX analysis.
Chromium
Cr has a very fine grain size, especially on semiconductor type materials and has proven to be a useful coating materials for FESEM applications. Cr requires the use of a turbo pumped, high vacuum, high resolution sputter coater with a target shutter since the presence of oxygen (as in standard SEM coaters) causes oxidisation during coating. The Cr on the sample surface will oxidise in air and samples must be viewed immediately after coating. Samples can be stored in high vacuum or in inert gas. Cr has lower sputtering rates and the target tends to heat up. Lower SE yield than Pt, Pt/Pd or Ir. Excellent coating material for high resolution BE imaging of low Z and biological samples.
Tungsten
W is an excellent alternative for ultra-high resolution coating.W has a very fine grain size and tends to be less visible than Cr. W oxidises rapidly, similar to Cr. Low sputtering rates, but due to the high atomic number the SE yield tends to be higher. Samples must be imaged immediately after coating or stored under high vacuum.
Tantalum
Ta is also a candidate for high resolution coating (most refractory and high melting materials exhibit fine grain size). It oxidises quite rapidly, similar to Cr. Low sputtering rates, but due to high atomic number the SE yield tends to be higher. Samples must be imaged immediately after coating or stored under high vacuum.
Palladium
Pd can be used as a lower cost alternative for low to medium magnification ranges. Gives a lower SE signal than Au. When using EDX analysis, Pd can be an alternative.
Nickel
Ni is an alternative coating material for EDX applications and BSE imaging. Not ideal for SE imaging, the coating oxidises slowly. It has a (very) low sputtering rate due to the low work function and the fact that as a magnetic materials it “short circuits” the magnet in the DC magnetron sputter head with a less dense plasma as a result. In a standard SEM coater, the coating contains a mixture of Ni and Ni-oxide. The Ni coating layer can enhance elements through X-ray fluorescence. If needed, the Ni coating can be removed if needed with a Hydrochloric acid or Nitric acid.
Copper
Cu is an alternative low cost material for EDX applications and BSE imaging. Suitable for low and medium magnification ranges. Lower SE yield. Coatings will slowly oxidize. In a standard SEM coater the coating consists of a mixture of Cu and Cu-oxide. However, it is a low cost alternative for educational applications to demonstrate and to investigate the influence of coating parameters. The Cu coating layer can be used to enhance the analysis of transition materials through X-ray fluorescence. If needed, the copper coating can be removed with Ferricchloride or Nitric Acid.
ITO – Indium Tin Oxide
ITO targets consist of In2O3 / SnO2 with a 90/10 wt% composition. ITO is an interesting material since it is electrically conductive and light transparent. One application for SEM is Cathodeluminescence imaging and/or analyzing of non-conductive samples with a detector/spectrometer. ITO is also useful for coating glass coverslips for correlative microscopy applications.
Titanium
Ti is seldom used as coating material, but has applications where it is chosen to avoid any interference with EDX analysis. Low atomic number gives less interference with BSE imaging. Ti oxidises quite rapidly and samples need to be imaged directly after coating.
Carbon
Carbon is the material of choice for coating non-conductive samples to allow for EDX analysis and BE imaging. It is has a low atomic number, is conductive and is inert at room temperature. It can’t be sputtered in DC magnetron sputter coaters; high energy is needed and if sputtered it tends to deposit as DLC material which is non-conductive. Carbon can be used as a target in ion-beam coaters such as the Gatan models 681, 682 and 685. Otherwise it is used in carbon evaporaters to coat SEM samples or to produce carbon support films for TEM.
Cobalt
Cobalt is not generally used for SEM coating applications. It has a (very) low sputtering rate due to the low work function and the fact that as a magnetic materials it “short circuits” the magnet in the DC magnetron sputter head with a less dense plasma as a result. In a standard SEM coater, the coating contains a mixture of Co and Co-oxide. The Co coating layer can enhance elements through X-ray fluorescence.
Indium
Indium is not generally used for SEM coating applications. It has a (very) low sputtering rate due to the low work function. In a standard SEM coater, the coating contains a mixture of In and In-oxide. The In coating layer can enhance elements through X-ray fluorescence
Tin
Tin is not generally used for SEM coating applications. It has a (very) low sputtering rate due to the low work function. In a standard SEM coater, the coating contains a mixture of Sn and Sn-oxide. The Sn coating layer can enhance elements through X-ray fluorescence.
Zinc
Zinc is not generally used for SEM coating applications. It has a (very) low sputtering rate due to the low work function. In a standard SEM coater, the coating contains a mixture of Zn and Zn-oxide. The Zn coating layer can enhance elements through X-ray fluorescence.
