Indium Tin Oxide In2O3/SnO2 90/10 wt % Evaporation Process Notes
Indium Oxide/Tin Oxide (In2O3/SnO2 90/10 WT%) is among one of the most heavily utilized compounds in the thin film industry due to its electrical conductivity and optical transparency. Specifically, the 90/10 WT% composition has a melting point of approximately 1,800°C and a density of 7.14 g/cc. The color of various ITO compounds range from pale yellow to dark green or dark grey. It is evaporated or sputtered under vacuum to generate transparent conductive layers in the manufacture of LCDs and various optical coatings. Thin films of ITO are created for the development of sensors, as well as, a glass coating for the automotive industry.
Indium Tin Oxide In2O3/SnO2 90/10 wt % Specifications
|Material Type||Indium Tin Oxide|
|Symbol||In2O3/SnO2 90/10 wt %|
|Melting Point (°C)||1,800|
|Theoretical Density (g/cc)||7.14|
|Max Power Density|
|Type of Bond||Indium, Elastomer|
|E-Beam Crucible Liner Material||FABMATE®, Graphite|
* This is a recommendation based on our experience running these materials in KJLC guns. The ratings are based on unbonded targets and are material specific. Bonded targets should be run at lower powers to prevent bonding failures. Bonded targets should be run at 20 Watts/Square Inch or lower, depending on the material.
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.