Trench isolation structure and forming method thereof, and semiconductor device and forming method thereof

Abstract

The invention provides a trench isolation structure and a forming method thereof, and a semiconductor device and a forming method thereof. The forming method of the trench isolation structure comprises the following steps: forming a trench isolation structure in a substrate, and defining an active region through the trench isolation structure, wherein the trench isolation structure is provided with a first isolation part and a second isolation part which are connected with each other, the second isolation part is located below the first isolation part, and the transverse width of the second isolation part in the direction perpendicular to the height direction is larger than the transverse width of the first isolation part in the direction perpendicular to the height direction, so that thesecond isolation part is enabled to protrude transversely relative to the first isolation part, so that the area of a leakage region is reduced, the equivalent resistance on a leakage path is increased, a leakage current is reduced, and the storage performance of the semiconductor device is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a trench isolation structure and a forming method thereof, a semiconductor device and a forming method thereof. Background technique [0002] At present, the existing integrated circuit memory can usually include several transistors. In order to reduce the area of ​​the integrated circuit memory to achieve the maximum integration, a trench type transistor structure is usually used. When the trench type transistor structure is used, the trench A leakage region is formed between the trench isolation structure and the gate structure of the storage transistor, and electrons between the source and drain regions of the storage transistor may migrate into the leakage region, thereby generating a leakage current, resulting in a decrease in the storage performance of the integrated circuit memory, Moreover, the larger the area of ​​the leakage region, the smaller the equivalent ...

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Problems solved by technology

[0002] At present, the existing integrated circuit memory can usually include several transistors. In order to reduce the area of ​​the integrated circuit memory to achieve the maximum integration, a trench type transistor structure is usually used. When the trench type transistor structure is used, the trench A leakage region is formed between the trench isolation structure and the gate structure of the storage transistor, and electrons between the source and drain regions of the storage transistor may migrate into the leakage region, thereby generating a leakage current, resulting in a decrease in the storage performance of the integrated circuit memory, And the larger the area of ​​the leakage area, the smaller the equivalent resistance on the leakage path, the greater the leakage current will be, and the worse the storage capacity of the integrated circuit memory is, how to reduce the leakage current has become an urgent problem to be solved

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