Method for forming active region and semiconductor device

Abstract

The invention provides an active region forming method and a semiconductor device. The active region forming method comprises the steps of: forming a base body structure, wherein the base body structure comprises a substrate in which shallow trenches are formed, preparation active regions formed in the substrate between the adjacent shallow trenches as well as a mask layer formed on the surface of the substrate, and through holes which correspond to the shallow trenches in position and are wider than the shallow trenches are formed in the mask layer; forming a first isolation medium layer, of which the upper surface is lower than the upper surface of the substrate, in each shallow trench; removing corners on two sides of each preparation active region via etching along the corresponding through hole; carrying out oxidation treatment on the preparation active regions along the through holes to form active regions with fillet parts; and forming second isolation medium layers connected with the first isolation medium layers in the through holes. The active region forming method can be used for forming the active regions with circular corners, thereby increasing the effective channel width of active devices in the active regions, and increasing operating current of the active devices.

Description

technical field [0001] The invention relates to a manufacturing process of a semiconductor integrated circuit, in particular to a method for forming an active region and a semiconductor device. Background technique [0002] In the manufacturing process of semiconductor devices, it is necessary to define the position of the active region in the substrate, and then form active devices such as transistors in the active region. When the active device is in the working state, a conductive channel is formed in the active region, and as the length of the conductive channel decreases or the width of the conductive channel increases, the operating current of the active device increases accordingly. At present, shallow trench isolation technology (Shallow Trench Isolation, STI) is usually used to define the position of the active region, that is, a trench isolation structure is formed in the substrate, and the substrate between adjacent trench isolation structures is used as the activ...

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Problems solved by technology

However, the active region formed by the above method has nearly right-angled corners, so that the effective channel width of the active device cannot be increased, and the operating current of the active device cannot be increased.

At the same time, in the above manufacturing method, the isolation dielectric layer is formed through a single deposition process, so that the bonding force between the isolation dielectric layer and the shallow trench is not high, thereby affecting the isolation effect of the trench isolation structure.

For the above problems, there is currently no effective solution

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