Doping

Doping

Doping is the most critical step for manufacturing transparent conductive film, because it is usually difficult to find material with both good transparency and conductivity. However, for manufacturing transparent conductive film, doping can integrate these two properties on one material.

Generally, doping is the process of intentionally adding impurities into the material to change materials’ electric properties. The impurities are called dopants. It is usually used in manufacturing semiconductors, but it is also widely applied in making raw material of transparent conductive film. The amount of impurities doped into the material is called contamination level.[27]

The working principle of doping is heat diffusion. Under high temperature, the dopants’ atoms move actively between the lattice and interstitials of the crystal structure of the doped material to take the place of the original material atoms.

The doping techniques can be classified into solid state proto-diffusion, liquid state proto-diffusion, and gas-state proto diffusion. In transparent conductive film, solid state diffusion is usually applied.

When doping, first, put the dopant material in a crucible and insert the substrate slice in a groove. Put the groove and crucible side by side in a diffusion furnace tube. Blow in inert gases such as argon and then heat it up to 800-900 ℃. The dopant atom will be taken to the surface of substrate slices by the flow of hot inert gas. After heating for long enough time, the dopants will diffuse into the substrate material.[26]

The process is as shown below.

Figure5.1 process of doping

[26]https://www.sciencedirect.com/topics/physics-and-astronomy/doping-materials

[27]https://www.sciencedirect.com/topics/chemistry/doping-material

Transparent Conductive Film

Transparent Conductive Film

6. Manufacturing

Confirm copying

Restore backup