PRESENTATION

THIN FILM TRANSISTOR

Presented by:ANMOL SOODRE6902B58LSE

INTRODUCTIONA thin film transistor comprises :•a semiconductor layer•a gate insulating layer•a gate electrodeThe semiconductor layer is typically a polysilicon layer whose electron mobility is 100 times higher than that of an amorphous silicon layer. Thin film transistors are used as switching devices in flat display panels such as organic light emitting diodes (OLEDs) or liquid crystal displays (LCDs).

Types:- IPS - in-plane switchingMVA - multi-domain vertical alignmentPVA - patterned vertical alignmentCPA - Continuous Pinwheel Alignment

WORKING:A voltage applied at the gate controls the

flow of electrons (resistance) from the source to the drain; a positive gate voltage attracts electrons to the bottom surface of the semiconductor layer and creates a conduction channel. When a voltage difference is applied between the two connector wires, electrons enter at one end (the source) and exit at the other (the drain), resulting in a current along the channel.

STRUCTURE:

STRUCTURE CONSISTS OF:1 - Glass plates2&3 - Horizontal and vertical polarizes4 - color mask5&6 - Horizontal and vertical command lines7 - Rugged polymer layer8 – Spacers9 - Thin film transistors10 - Front electrode11 - Rear electrodes

MANUFACTURE:ManufactureTFTs can be made using a wide variety of semiconductor

materials. A common material is silicon. The characteristics of a silicon based TFT depend on the crystalline state. That is, the semiconductor layer can be either amorphous silicon, microcrystalline silicon, or it can be polysilicon.

Other materials which have been used as semiconductors in TFTs include compound semiconductors such as cadmium selenide and metal oxides such as Zinc Oxide. TFT's have also been made using organic materials.

By using transparent semiconductors and transparent electrodes, such as indium tin oxide (ITO), some TFT devices can be made completely transparent.

1. High transparency : available for transparent TFTs

2. Room temperature process : available for plastics substrate

3. Can be used as electrodes, or channel layers.

4. High field effect mobility : 10 ~ 50 cm2V-1S-1

5. Large area deposition

6. Rapid Process

7. Low cost

8. Low leakage current.

Advantages of the Thin Film Transistors