Tantalum Pentoxide (Ta₂0₅) Tablets Evaporation Materials

Tantalum Pentoxide (Ta₂0₅) Tablets Overview

We sell these pellets and pieces by unit weight for evaporation use in deposition processes. These approximate materials prices are published to provide budgetary guidelines. Actual prices can vary and may be higher or lower, as determined by availability and market fluctuations. To speak to someone directly about current pricing, please click here .

Tantalum Pentoxide (Ta₂0₅) General Information

Tantalum oxide is an inorganic chemical compound with a chemical formula of Ta₂O₅. It is crystalline solid and white in appearance with a density of 8.2 g/cc, a melting point of 1,872°C, and a vapor pressure of 10^-4 Torr at 1,920°C. It is mainly used to produce capacitors which can be found in auto electronics, cell phones, and tools. Tantalum oxide can also be found in the glass for camera lenses. It is evaporated under vacuum to form films for the fabrication of semiconductors, optoelectronic devices, and fuel cells.

Tantalum Pentoxide (Ta₂0₅) Specifications

**** Suggestion based on previous experience but could vary by process. Contact local KJLC Sales Manager for further information

Z-Factors

Empirical Determination of Z-Factor

Unfortunately, Z Factor and Shear Modulus are not readily available for many materials. In this case, the Z-Factor can also be determined empirically using the following method:

• Deposit material until Crystal Life is near 50%, or near the end of life, whichever is sooner.
• Place a new substrate adjacent to the used quartz sensor.
• Set QCM Density to the calibrated value; Tooling to 100%
• Zero thickness
• Deposit approximately 1000 to 5000 A of material on the substrate.
• Use a profilometer or interferometer to measure the actual substrate film thickness.
• Adjust the Z Factor of the instrument until the correct thickness reading is shown.

Another alternative is to change crystals frequently and ignore the error. The graph below shows the % Error in Rate/Thickness from using the wrong Z Factor. For a crystal with 90% life, the error is negligible for even large errors in the programmed versus actual Z Factor.

Thermal Evaporation of Tantalum Pentoxide (Ta₂0₅)

Tantalum oxide is not recommended for thermal evaporation because the temperatures required to reach a reasonable deposition rate will likely exceed those acceptable in most vacuum chambers. E-beam is the preferred method to deposit tantalum oxide films.

If thermal evaporation is the only option, we would recommend using a tantalum boat such as our EVS8B005TA. Pressure should be monitored to ensure outgassing is at an acceptable level before increasing power. We estimate a deposition rate of 2-5 angstroms per second when the evaporation temperature is at ~2,000°C. A partial pressure of O₂ at 1 X 10^-4 Torr is recommended. Post deposition bake out at 400°C in air for four hours eliminates residual absorption.

It is important to note that evaporation temperatures likely exceed the temperatures reasonable to evaporate via resistive heating.

E-beam Evaporation of Tantalum Pentoxide (Ta₂0₅)

E-beam evaporation is preferred over thermal evaporation for depositing tantalum oxide films. We recommend using a FABMATE^® or tantalum crucible liner.

We recommend sweeping the e-beam at low power to uniformly fuse the surface of the pieces and to avoid hole drilling. Pressure should be monitored to ensure outgassing is at an acceptable level before increasing power. If possible, Ion Assisted Deposition (IAD) is preferred. We estimate a deposition rate of 2-5 angstroms per second when the evaporation temperature is at ~2,000°C. A partial pressure of O₂ at 1 X 10^-4 Torr is also recommended. Post deposition bake out at 400°C in air for four hours eliminates residual absorption. Under these parameters, we expect hard, scratch-resistant films with good adhesion.

Another key process note is to consider the fill volume in the e-beam application because 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. This is the most common cause of crucible liner failure. Placing too little material in the crucible 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.