Component comprising a thin-film transistor and CMOS-transistors and methods for production
Assigneeaustriamicrosystms AG
InventorHubert Enichlmair
Life of this patent
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Abstract
An electrical component, in the crystalline semiconductor body of which several CMOS transistors in high-voltage or low-voltage technology are formed. The individual CMOS transistors are separated from one another by insulation regions. On one insulation region, a thin-film transistor is formed, having a gate that is realized simultaneously with the gates of the CMOS transistors from the same polysilicon layer. The gate oxide of the thin-film transistor, just like a second polysilicon layer for source drain and body of the thin-film transistor, can be produced together with the structural elements already present in the CMOS process.
Claims15
A semiconductor component comprising:
- a substrate that comprises a crystalline semiconductor body;
- several CMOS transistors formed in the semiconductor body;
- insulation regions formed between the CMOS transistors for mutual electrical isolation that comprise field oxide regions or STI regions;
- an additional insulation region that has a larger surface area than the other insulation regions;
- a thin-film transistor with a gate arranged on the additional insulation region;
- a first polysilicon layer;
- and
- a second polysilicon layer,
- wherein both a gate of a CMOS transistor and a gate of the thin-film transistor are formed in the first polysilicon layer and therefore have the same layer thickness and crystal structure,
- wherein the thin-film transistor has a source, a body and a drain that are formed in the second polysilicon layer, which also serves for structural elements of the CMOS transistors, and
- wherein the source and drain of the thin-film transistor are formed on either side of the gate in the second polysilicon layer by a p+-type or n+-type doping.
A method for manufacturing a component with CMOS transistors and at least one thin-film transistor, comprising the steps of:
- electrically isolating the active regions for the CMOS transistors from one another in a semiconductor body by insulation regions by producing field oxide regions or STI regions, wherein at least one insulation region is formed, as a base for the at least one thin-film transistor, with a larger surface area than is necessary for pure insulation between the CMOS transistors;
- producing, in the same common process, both the gate of the CMOS transistors above a layer of a gate dielectric and simultaneously the gate of the thin-film transistor on the flat insulation region by depositing and structuring a first polysilicon layer for a poly-1 level;
- applying a second polysilicon layer, which overlaps the gate of the thin-film transistor and is structured into source, drain and body of the thin-film transistor, wherein structural elements of the poly-2 level of the CMOS transistor are simultaneously produced;
- and
- forming a source and drain of the thin-film transistor on either side of the gate in the second polysilicon layer by a p+-type or n+-type doping.
Dependencies are inferred from the claim text.