Transistor structure
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChen-Liang Chu, Chien-Chih Chou, Ta-Yuan Kung, Chun-Hsun Lee, Chih-Wen Yao, Yi-Huan Chen, Ming-Ta Lei
Life of this patent
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Abstract
Transistors with improved saturation drain current and methods for making such transistors are disclosed. The gate is formed in the shape of a longitudinal trench and a plurality of lateral trenches below the longitudinal trench. The resulting dual-recess structure increases the surface area of the gate, which permits additional charge carriers and increases the saturation drain current of the transistor. Such transistors can be useful in high voltage and medium voltage applications such as in display driver integrated circuits.
Claims20
A method for increasing the saturation drain current of a transistor, comprising:
- etching a substrate to form a longitudinal trench that defines a gate region;
- etching the longitudinal trench to form a plurality of lateral trenches in the longitudinal trench, wherein the longitudinal trench and the plurality of lateral trenches together define a gate volume, and wherein the lateral trenches extend between a source terminal and a drain terminal;
- forming a gate oxide layer in the gate volume;
- and
- depositing a gate material in the gate volume to form a gate terminal.
A display driver integrated circuit that includes a transistor comprising:
- a source terminal, a drain terminal, and a gate terminal formed in a substrate;
- wherein the gate terminal is located between the source terminal and the drain terminal;
- and
- wherein the gate terminal comprises a longitudinal trench and lateral trenches below the longitudinal trench which are filled with a gate material, and wherein the lateral trenches extend between the source terminal and the drain terminal.
A method for increasing the saturation drain current of a transistor, comprising:
- forming an isolation region in a substrate to define an active region;
- recessing a first portion of the active region, wherein a top surface of a second portion of the active region is higher than a top surface of the recessed first portion of the active region;
- forming a plurality of trenches in the top surface of the recessed first portion of the active region, the recessed first portion and the plurality of trenches together defining a gate volume;
- forming a gate structure in the gate volume;
- and
- forming source/drain terminals in second portions of the active region.
Dependencies are inferred from the claim text.