Selectively doped trench device isolation
OwnerDavid Kao, Rongsheng Yanginventors
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Abstract
A selectively doped trench isolation device is provided. The trench isolation device of the preferred embodiment includes a semiconductor substrate having a trench. A thin field oxide layer is grown on the side walls of the trench, and the trench is filled with a heavily doped polysilicon. The work function difference between the substrate and the heavily doped polysilicon increases the field threshold voltage of the gated trench isolation device so that smaller isolation structures can be formed between adjacent active devices in higher density integrated circuits.
Claims16
A method of forming an isolation device on a field region of a substrate comprising:
- forming a trench in the substrate wherein said trench defines a trench surface;
- forming a first material layer on said surface wherein said first material is comprised of an insulating material;
- filling said trench with a second material having a work function value higher than the work function value of the substrate;
- and
- applying an electrical bias on said second material so as to induce a field threshold voltage into said field region wherein said field threshold voltage inhibits electrical conduction in that field region.
A semiconductor integrated circuit comprising;
- a semiconductor substrate having a first work function value, said substrate defines a first active area having a first active device and a second active area having a second active device;
- and
- an isolation structure which includes a trench formed in said substrate between said first and second active areas and further includes an insulating layer positioned on the side walls of said trench and a second material filling said trench so that said insulating layer is interposed between the substrate and the second material wherein said second material comprises a material having a second work function value which is greater than the first work function value of said substrate.
Dependencies are inferred from the claim text.