Polysilicon thin film transistor and method of forming the same
AssigneeAu Optronics Corporation
InventorsKun-Hong Chen, Chinwei Hu
Life of this patent
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Abstract
A polysilicon thin film transistor and a method of forming the same is provided. A poly-island layer is formed over a substrate. A gate insulation layer is formed over the poly-island layer. A gate is formed over the gate insulation layer. Using the gate as a mask, an ion implantation of the poly-island layer is carried out to form a source/drain region in the poly-island layer outside the channel region. An oxide layer and a silicon nitride layer, together serving as an inter-layer dielectric layer, are sequentially formed over the substrate. Thickness of the oxide layer is thicker than or the same as (thickness of the nitride layer multiplied by 9000 Å)1/2 and maximum thickness of the nitride layer is smaller than 1000 Å.
Claims5
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:
- Tox≧(Tnitride×9000 Å)1/2, where Tox represents the thickness of the oxide layer (in Å), Tnitride represents thickness of the silicon nitride layer and that thickness of the nitride layer is between 50 Å and 1000 Å.
Dependencies are inferred from the claim text.