Molybdenum Mo Evaporation Process Notes

Thermal Evaporation of Molybdenum (Mo)

In a deposition system with normal dimensions, a material with an equilibrium vapor pressure (EVP) of 10^-2 Torr will deposit at a rapid rate. Therefore, 10^-2 Torr is typically regarded as the EVP one should attempt to achieve during deposition. The only parameter that affects EVP is temperature. We reference various charts or books to determine what temperature is needed to make the material's EVP 10^-2 Torr. Molybdenum requires a temperature of ~2,600°C to achieve a vapor pressure of 10^-2 Torr.

Molybdenum (Mo) Vapor Pressure Chart

Molybdenum is nearly impossible to deposit by thermal evaporation due to the high power required for the material to evaporate. E-beam evaporation or magnetron sputtering are the recommended methods for molybdenum deposition.

E-beam Evaporation of Molybdenum (Mo)

In a deposition system with normal dimensions, a material with an equilibrium vapor pressure (EVP) of 10^-2 Torr will deposit at a rapid rate. Therefore, 10^-2 Torr is typically regarded as the EVP one should attempt to achieve during deposition. The only parameter that affects EVP is temperature. We reference various charts or books to determine what temperature is needed to make the material's EVP 10^-2 Torr. Molybdenum requires a temperature of ~2,600°C to achieve a vapor pressure of 10^-2 Torr.

Molybdenum (Mo) Vapor Pressure Chart

Molybdenum is rated 'excellent' for e-beam evaporation. However, the process can be difficult and should be monitored very closely. Pre-melting molybdenum is a challenge as it tends to not melt into the beam as most metals do.

Due to its high melting point (2,617°C), molybdenum requires high powers in order to achieve an effective deposition rate. At a working voltage of 10kV, we found that 140-150 mA of current was needed in order to reach an acceptable evaporation rate using a FABMATE^® crucible liner and molybdenum slug (or starter source). Even at these powers, we have only been able to achieve a deposition rate of 2.2 angstroms per second. Maintaining a deposition rate is also difficult to do. There is risk that the e-beam will bore straight through the material which is evidenced by a sudden and steep fall-off of the deposition rate. While running at these high currents (>125mA), it is possible for the e-beam to then drill a hole through the crucible liner and into the e-gun hearth. For these reasons, the e-beam evaporation of molybdenum should be closely monitored through welder's shade 9 glass. Great care should be taken during the entire evaporation cycle.

Another common problem when e-beam evaporating molybdenum is spitting. Soaking the material for an extended period of time before opening the substrate shutter to deposit the film can reduce this to some degree. Spitting can also be reduced by using a starter source or rod as opposed to evaporation pellets.

We recommend using a pre-machined slug (or starter source) instead of pellets. The two main benefits of using a starter source are ease of use and handling as well as superior packing density. We have found that using a rod for high temperature materials like molybdenum helps reduce the amount of power required for deposition. We machine a rod such that the outer diameter of the rod is not in contact with the cooled walls of the crucible liner. This allows higher temperatures to be achieved at lower powers. Molybdenum will still require high power for evaporation even when using a starter source or rod, but less so than when using pellets.

KJLC^® can produce these starter sources or rods. Contact us by clicking here with your e-gun manufacturer, pocket size, and number of pockets in order for us to produce a quote.

We also recommend using a FABMATE^® or graphite crucible liner or running molybdenum directly from the hearth of the e-gun. Because not using a crucible liner is not always an option, especially in shared systems, some customers will use a copper crucible liner and place the material in the copper crucible liner instead of placing directly in the hearth.

A key process note is to consider the fill volume of the crucible liner. We find that the melt level of a material in the crucible directly affects the success of the crucible liner. Overfilling the crucible will cause the material to spill over and create an electrical short between the liner and the hearth. The outcome is cracking in the crucible liner. This is the most common cause of crucible liner failure. Placing too little material in the liner or evaporating too much material before refilling can be detrimental to the process as well. When the melt level is below 30%, the e-beam is likely to strike the bottom or walls of the crucible which immediately results in breakage. Our recommendation is to fill the crucible between 2/3 and 3/4 full to prevent these difficulties.

Crucible liners should be stored in a cool, dry place and always handled with gloves or forceps.

E-beam Crucible Liner Fill Rate Calculator

Instructions for use:
Input the Crucible Liner Volume, Select Material (if not available in menu, manually input Material Density in g/cm³), and input fill rate %.

KJLC recommends a fill rate between 67-75%. Overfilling the crucible will cause the material to spill over and create an electrical short between the liner and the hearth causing the crucible to crack. Placing too little material in the crucible or allowing the melt level to get too low can be detrimental to the process as well. When the melt level is below 30%, the e-beam is likely to strike the bottom or walls of the crucible which immediately results in breakage.

The fill rate above assumes that the material is fully melted and does not take into account packing density. It should be noted that the crucible liner may need to be loaded multiple times, pre-melted, and topped off in order to achieve the final desired melt level/fill rate. When loading the crucible, do not load more than 80% of the height of the crucible liner.

This calculator is for estimation purposes only.

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Crucible Liner Volume (in cc):

Material:
-- Please Select -- Aluminum Aluminum Antimonide Aluminum Arsenide Aluminum Bromide Aluminum Carbide Aluminum Fluoride Aluminum Nitride Aluminum Oxide Aluminum Phosphide Aluminum, 1% Copper Aluminum, 1% Silicon Antimony Antimony Oxide Antimony Selenide Antimony Sulfide Antimony Telluride Arsenic Arsenic Oxide Arsenic Selenide Arsenic Sulfide Arsenic Telluride Barium Barium Chloride Barium Fluoride Barium Oxide Barium Sulfide Barium Titanate Beryllium Beryllium Carbide Beryllium Chloride Beryllium Fluoride Beryllium Oxide Bismuth Bismuth Fluoride Bismuth Oxide Bismuth Selenide Bismuth Sulfide Bismuth Telluride Bismuth Titanate Boron Boron Carbide Boron Nitride Boron Oxide Boron Sulfide Cadmium Cadmium Antimonide Cadmium Arsenide Cadmium Bromide Cadmium Chloride Cadmium Fluoride Cadmium Iodide Cadmium Oxide Cadmium Selenide Cadmium Sulfide Cadmium Telluride Calcium Calcium Fluoride Calcium Oxide Calcium Silicate Calcium Sulfide Calcium Titanate Calcium Tungstate Carbon Cerium Cerium (III) Oxide Cerium (IV) Oxide Cerium Fluoride Cesium Cesium Bromide Cesium Chloride Cesium Fluoride Cesium Hydroxide Cesium Iodide Chiolite Chromium Chromium (II) Bromide Chromium Boride Chromium Carbide Chromium Chloride Chromium Oxide Chromium Silicide Cobalt † Cobalt Bromide Cobalt Chloride Cobalt Oxide Copper Copper Chloride Copper Oxide Copper Sulfide Cryolite Dysprosium Dysprosium Fluoride Dysprosium Oxide Erbium Erbium Fluoride Erbium Oxide Europium Europium Fluoride Europium Oxide Europium Sulfide Gadolinium † Gadolinium Carbide Gadolinium Oxide Gallium Gallium Antimonide Gallium Arsenide Gallium Nitride Gallium Oxide Gallium Phosphide Germanium Germanium (II) Oxide Germanium (III) Oxide Germanium Nitride Germanium Telluride Glass, Schott^® 8329 Gold Hafnium Hafnium Boride Hafnium Carbide Hafnium Nitride Hafnium Oxide Hafnium Silicide Holmium Holmium Fluoride Holmium Oxide Inconel^® Indium Indium (I) Oxide Indium (I) Sulfide Indium (II) Sulfide Indium (II) Telluride Indium (III) Oxide Indium (III) Sulfide Indium (III) Telluride Indium Antimonide Indium Arsenide Indium Nitride Indium Phosphide Indium Selenide Indium Tin Oxide Iridium Iron (II) Oxide Iron (III) Oxide Iron † Iron Bromide Iron Chloride Iron Iodide Iron Sulfide Kanthal Lanthanum Lanthanum Boride Lanthanum Bromide Lanthanum Fluoride Lanthanum Oxide Lead Lead Bromide Lead Chloride Lead Fluoride Lead Iodide Lead Oxide Lead Selenide Lead Stannate Lead Sulfide Lead Telluride Lead Titanate Lithium Lithium Bromide Lithium Chloride Lithium Fluoride Lithium Iodide Lithium Niobate Lithium Oxide Lutetium Lutetium Oxide Magnesium Magnesium Aluminate Magnesium Bromide Magnesium Chloride Magnesium Fluoride Magnesium Iodide Magnesium Oxide Manganese Manganese (II) Oxide Manganese (III) Oxide Manganese (IV) Oxide Manganese Bromide Manganese Chloride Manganese Sulfide Mercury Mercury Sulfide Molybdenum Molybdenum Boride Molybdenum Carbide Molybdenum Oxide Molybdenum Silicide Molybdenum Sulfide Neodymium Neodymium Fluoride Neodymium Oxide Nichrome IV^® Nickel † Nickel Bromide Nickel Chloride Nickel Oxide Nickel/Iron † Nimendium † Niobium Niobium (II) Oxide Niobium (III) Oxide Niobium (V) Oxide Niobium Boride Niobium Carbide Niobium Nitride Niobium Telluride Niobium-Tin Osmium Osmium Oxide Palladium Palladium Oxide Parylene Permalloy^® † Phosphorus Phosphorus Nitride Platinum Platinum Oxide Plutonium Polonium Potassium Potassium Bromide Potassium Chloride Potassium Fluoride Potassium Hydroxide Potassium Iodide Praseodymium Praseodymium Oxide PTFE Radium Rhenium Rhenium Oxide Rhodium Rubidium Rubidium Chloride Rubidium Iodide Ruthenium Samarium Samarium Oxide Samarium Sulfide Scandium Scandium Oxide Selenium Silicon Silicon (II) Oxide Silicon (IV) Oxide Silicon (N-type) Silicon (P-type) Silicon Boride Silicon Carbide Silicon Nitride Silicon Selenide Silicon Sulfide Silicon Telluride Silver Silver Bromide Silver Chloride Silver Iodide Sodium Sodium Bromide Sodium Chloride Sodium Cyanide Sodium Fluoride Sodium Hydroxide Spinel Strontium Strontium Chloride Strontium Fluoride Strontium Oxide Strontium Sulfide Strontium Titanate Sulfur Supermalloy^® † Tantalum Tantalum Boride Tantalum Carbide Tantalum Nitride Tantalum Pentoxide Tantalum Sulfide Technetium Tellurium Terbium Terbium Fluoride Terbium Oxide Terbium Peroxide Thallium Thallium Bromide Thallium Chloride Thallium Iodide Thallium Oxide Thorium Thorium Bromide Thorium Carbide Thorium Fluoride Thorium Oxide Thorium Oxyfluoride Thorium Sulfide Thulium Thulium Oxide Tin Tin Oxide Tin Selenide Tin Sulfide Tin Telluride Titanium Titanium (II) Oxide Titanium (III) Oxide Titanium (IV) Oxide Titanium Boride Titanium Carbide Titanium Nitride Tungsten Tungsten Boride Tungsten Carbide Tungsten Disulfide Tungsten Oxide Tungsten Selenide Tungsten Silicide Tungsten Telluride Uranium Uranium (II) Sulfide Uranium (III) Oxide Uranium (IV) Oxide Uranium (IV) Sulfide Uranium Carbide Uranium Fluoride Uranium Phosphide Vanadium Vanadium (IV) Oxide Vanadium (V) Oxide Vanadium Boride Vanadium Carbide Vanadium Nitride Vanadium Silicide Ytterbium Ytterbium Fluoride Ytterbium Oxide Yttrium Yttrium Aluminum Oxide Yttrium Fluoride Yttrium Oxide Zinc Zinc Antimonide Zinc Bromide Zinc Fluoride Zinc Nitride Zinc Oxide Zinc Selenide Zinc Sulfide Zinc Telluride Zirconium Zirconium Boride Zirconium Carbide Zirconium Nitride Zirconium Oxide Zirconium Silicate Zirconium Silicide
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Density of the material in g/cm³:

Fill Rate %:

Result

See highlighted results that match your result in the table below.

Material Needed to Deposit a 1 Micron Film Calculator

Instructions for use:
Select source type, input distance from source to substrate and Select Material (if not available in menu, manually input Material Density in kg/m³).

This calculator is for estimation purposes only. The estimated mass is that needed to produce a desired film thickness (1 micron in this case) on a flat substrate at a point directly above the source, accounting for the approximate plume distribution of the selected source type. It does not account for any expected nonuniformity in thickness over a larger substrate area. More complex geometries, e.g. those with offset and/or tilted sources, may have higher material requirements. The estimated mass is for the film deposition only; additional margin should be included to account for loss during ramp-up, burn-in, stabilisation and ramp-down.

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Source:
Point Directional - Thermal Boat Directional - EBeam Directional - LTE/HTE

Distance of source to substrate (in cm):

Material:
-- Please Select -- Aluminum Aluminum Antimonide Aluminum Arsenide Aluminum Bromide Aluminum Carbide Aluminum Fluoride Aluminum Nitride Aluminum Oxide Aluminum Phosphide Aluminum, 1% Copper Aluminum, 1% Silicon Antimony Antimony Oxide Antimony Selenide Antimony Sulfide Antimony Telluride Arsenic Arsenic Oxide Arsenic Selenide Arsenic Sulfide Arsenic Telluride Barium Barium Chloride Barium Fluoride Barium Oxide Barium Sulfide Barium Titanate Beryllium Beryllium Carbide Beryllium Chloride Beryllium Fluoride Beryllium Oxide Bismuth Bismuth Fluoride Bismuth Oxide Bismuth Selenide Bismuth Sulfide Bismuth Telluride Bismuth Titanate Boron Boron Carbide Boron Nitride Boron Oxide Boron Sulfide Cadmium Cadmium Antimonide Cadmium Arsenide Cadmium Bromide Cadmium Chloride Cadmium Fluoride Cadmium Iodide Cadmium Oxide Cadmium Selenide Cadmium Sulfide Cadmium Telluride Calcium Calcium Fluoride Calcium Oxide Calcium Silicate Calcium Sulfide Calcium Titanate Calcium Tungstate Carbon Cerium Cerium (III) Oxide Cerium (IV) Oxide Cerium Fluoride Cesium Cesium Bromide Cesium Chloride Cesium Fluoride Cesium Hydroxide Cesium Iodide Chiolite Chromium Chromium (II) Bromide Chromium Boride Chromium Carbide Chromium Chloride Chromium Oxide Chromium Silicide Cobalt † Cobalt Bromide Cobalt Chloride Cobalt Oxide Copper Copper Chloride Copper Oxide Copper Sulfide Cryolite Dysprosium Dysprosium Fluoride Dysprosium Oxide Erbium Erbium Fluoride Erbium Oxide Europium Europium Fluoride Europium Oxide Europium Sulfide Gadolinium † Gadolinium Carbide Gadolinium Oxide Gallium Gallium Antimonide Gallium Arsenide Gallium Nitride Gallium Oxide Gallium Phosphide Germanium Germanium (II) Oxide Germanium (III) Oxide Germanium Nitride Germanium Telluride Glass, Schott^® 8329 Gold Hafnium Hafnium Boride Hafnium Carbide Hafnium Nitride Hafnium Oxide Hafnium Silicide Holmium Holmium Fluoride Holmium Oxide Inconel^® Indium Indium (I) Oxide Indium (I) Sulfide Indium (II) Sulfide Indium (II) Telluride Indium (III) Oxide Indium (III) Sulfide Indium (III) Telluride Indium Antimonide Indium Arsenide Indium Nitride Indium Phosphide Indium Selenide Indium Tin Oxide Iridium Iron (II) Oxide Iron (III) Oxide Iron † Iron Bromide Iron Chloride Iron Iodide Iron Sulfide Kanthal Lanthanum Lanthanum Boride Lanthanum Bromide Lanthanum Fluoride Lanthanum Oxide Lead Lead Bromide Lead Chloride Lead Fluoride Lead Iodide Lead Oxide Lead Selenide Lead Stannate Lead Sulfide Lead Telluride Lead Titanate Lithium Lithium Bromide Lithium Chloride Lithium Fluoride Lithium Iodide Lithium Niobate Lithium Oxide Lutetium Lutetium Oxide Magnesium Magnesium Aluminate Magnesium Bromide Magnesium Chloride Magnesium Fluoride Magnesium Iodide Magnesium Oxide Manganese Manganese (II) Oxide Manganese (III) Oxide Manganese (IV) Oxide Manganese Bromide Manganese Chloride Manganese Sulfide Mercury Mercury Sulfide Molybdenum Molybdenum Boride Molybdenum Carbide Molybdenum Oxide Molybdenum Silicide Molybdenum Sulfide Neodymium Neodymium Fluoride Neodymium Oxide Nichrome IV^® Nickel † Nickel Bromide Nickel Chloride Nickel Oxide Nickel/Iron † Nimendium † Niobium Niobium (II) Oxide Niobium (III) Oxide Niobium (V) Oxide Niobium Boride Niobium Carbide Niobium Nitride Niobium Telluride Niobium-Tin Osmium Osmium Oxide Palladium Palladium Oxide Parylene Permalloy^® † Phosphorus Phosphorus Nitride Platinum Platinum Oxide Plutonium Polonium Potassium Potassium Bromide Potassium Chloride Potassium Fluoride Potassium Hydroxide Potassium Iodide Praseodymium Praseodymium Oxide PTFE Radium Rhenium Rhenium Oxide Rhodium Rubidium Rubidium Chloride Rubidium Iodide Ruthenium Samarium Samarium Oxide Samarium Sulfide Scandium Scandium Oxide Selenium Silicon Silicon (II) Oxide Silicon (IV) Oxide Silicon (N-type) Silicon (P-type) Silicon Boride Silicon Carbide Silicon Nitride Silicon Selenide Silicon Sulfide Silicon Telluride Silver Silver Bromide Silver Chloride Silver Iodide Sodium Sodium Bromide Sodium Chloride Sodium Cyanide Sodium Fluoride Sodium Hydroxide Spinel Strontium Strontium Chloride Strontium Fluoride Strontium Oxide Strontium Sulfide Strontium Titanate Sulfur Supermalloy^® † Tantalum Tantalum Boride Tantalum Carbide Tantalum Nitride Tantalum Pentoxide Tantalum Sulfide Technetium Tellurium Terbium Terbium Fluoride Terbium Oxide Terbium Peroxide Thallium Thallium Bromide Thallium Chloride Thallium Iodide Thallium Oxide Thorium Thorium Bromide Thorium Carbide Thorium Fluoride Thorium Oxide Thorium Oxyfluoride Thorium Sulfide Thulium Thulium Oxide Tin Tin Oxide Tin Selenide Tin Sulfide Tin Telluride Titanium Titanium (II) Oxide Titanium (III) Oxide Titanium (IV) Oxide Titanium Boride Titanium Carbide Titanium Nitride Tungsten Tungsten Boride Tungsten Carbide Tungsten Disulfide Tungsten Oxide Tungsten Selenide Tungsten Silicide Tungsten Telluride Uranium Uranium (II) Sulfide Uranium (III) Oxide Uranium (IV) Oxide Uranium (IV) Sulfide Uranium Carbide Uranium Fluoride Uranium Phosphide Vanadium Vanadium (IV) Oxide Vanadium (V) Oxide Vanadium Boride Vanadium Carbide Vanadium Nitride Vanadium Silicide Ytterbium Ytterbium Fluoride Ytterbium Oxide Yttrium Yttrium Aluminum Oxide Yttrium Fluoride Yttrium Oxide Zinc Zinc Antimonide Zinc Bromide Zinc Fluoride Zinc Nitride Zinc Oxide Zinc Selenide Zinc Sulfide Zinc Telluride Zirconium Zirconium Boride Zirconium Carbide Zirconium Nitride Zirconium Oxide Zirconium Silicate Zirconium Silicide
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Density of the material in kg/m³:

Multiplier:

Mass for 1 micron layer