ITOs & Other TCOs

Filmetrics Applications (Thickness Measurement) – ITOs & Other TCOs

Liquid crystal displays, the multitude of organic light-emitting diode (OLED) variants, and most other flat-panel display technologies rely on transparent conductive oxides (TCOs) such as indium tin oxide (ITO) to transport current and to serve as the anode for each light-emitting element.

Knowing the thickness of the layers that form the display is an important advantage in any thin-film process.  For LCDs, determining thickness requires a way to measure the polyimide and liquid crystal layers in addition to the ITO layer.  For OLEDs, a thickness measurement must examine the emitting, injecting, and encapsulation layers.

In measuring any multilayer stack, optical techniques such as spectral reflectance and ellipsometry require the thickness and optical constants (refractive index and k) of every layer in the stack to be either measured or accurately modeled.

When that stack contains an ITO layer, it becomes more challenging to measure and model the other layers.  This is because ITO has a unique spectral signal that generally dominates the other layers.  The refractive index of the ITO layer must be measured accurately in order to then determine the thickness of the other material layers.

In addition, an accurate refractive index measurement of the ITO layer is important to confirm that the compound used will deliver the right level of conductivity, or to verify the thickness of an ITO film that is built into display glass.

The Filmetrics Solution for Measuring ITO Thickness

The Filmetrics F20-EXR uses spectral reflectance to deliver a simple and affordable solution for accurate ITO measurements.  This solution combines a new ITO dispersion model with the wide 400-1700nm wavelength range of the Filmetrics F20-EXR to provide robust, "one-click" analysis of ITO thickness.  Once the ITO layer is characterized, the Filmetrics F20-EXR can analyze the remaining display layers.

Whether you are involved in basic research or display manufacturing, Filmetrics can deliver the capabilities you need to measure…

            Liquid crystal layers

* Polyimide, hardcoat, and liquid crystal thickness

            OLED Layers

            * Emission, injection, buffer, and encapsulation

For non-patterned samples, consider the Filmetrics F20 family of film-measurement instruments.  For patterned films, the Filmetrics F40 and F42 products for measuring film thickness have found wide use in display applications.

Premier Solutions Pte Ltd / Filmetrics Applications (Thickness Measurement / Thin Film Measurement ) – – ITOs & Other TCOs