Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
106 words
A process for manufacturing a thin film transistor, characterised by the steps of forming a first polysilicon layer (9) on a substrate (10); forming a silicon dioxide layer (11) on a region of the first polysilicon layer leaving exposed regions (14,15) of said first polysilicon layer; forming a second polysilicon layer (12) on the silicon dioxide layer and aligned therewith; and depositing on the second polysilicon layer and on the exposed regions of the first polysilicon layer, regions (18,19,20) of a selectively-grown electrically-conductive film (13), which film will not grow on the edges (16,17) of the silicon dioxide layer but will grow on the exposed polysilicon.
Claim 2
Dependent Claim
106 words
A process for manufacturing a thin film transistor, characterised by the steps of forming a first polysilicon layer (9) on a substrate (10); forming a silicon dioxide layer (11) on a region of the first polysilicon layer leaving exposed regions (14,15) of said first polysilicon layer; forming a second polysilicon layer (12) on the silicon dioxide layer and aligned therewith; and depositing on the second polysilicon layer and on the exposed regions of the first polysilicon layer, regions (18,19,20) of a selectively-grown electrically-conductive film (13), which film will not grow on the edges (16,17) of the silicon dioxide layer but will grow on the exposed polysilicon.
Claim 3
Dependent Claim
19 words
A process as claimed in Claim 1, characterised in that the electrically-conductive film (13) is a layer of tungsten.
Claim 4
Dependent Claim
35 words
A process as claimed in Claim 2, characterised in that the deposition step comprises introducing tungsten hexafluoride gas into an evacuated chamber containing the substrate (10) with the polysilicon and silicon dioxide layers (9,12,11) thereon.
Claim 5
Dependent Claim
29 words
A process as claimed in Claim 3, characterised in that during the deposition step the temperature of the substrate (10) is maintained in the range of 350° to 450°C.
Claim 6
Dependent Claim
57 words
A process as claimed in any preceding claim, characterised in that after the deposition of the film (13), the substrate (10) with said layers (9,12,11) and film (13) thereon is heated to cause diffusion of the material of the film into the regions (14,15) of the first polysilicon layer (19) and into the second polysilicon layer (12).