Patent ID: 6887745

Claim:
A method of forming a polysilicon thin film transistor, comprising the steps of: forming a poly-island layer over a substrate; forming a gate insulation layer over the poly-island layer; forming a gate electrode over the gate insulation layer above a section of the poly-island layer destined for forming a channel region; conducting an ion implantation of the poly-island layer using the gate electrode as a mask to form source/drain regions in the poly-island layer outside the channel region; and sequentially forming an oxide layer and a nitride layer over the substrate to cover the gate electrode and the gate insulation layer, wherein the oxide layer and the nitride layer serving as an inter-layer dielectric layer have a thickness relationship given by the equation: T ox â‰§(T nitride Ã—9000 â„«) 1/2 , where T ox represents the thickness of the oxide layer (in â„«), T nitride represents thickness of the silicon nitride layer and that thickness of the nitride layer is between 50 â„« and 1000 â„«.