Semiconductor structures and methods of forming them

Abstract

The invention discloses a semiconductor structure and a forming method therefor, and the method comprises the steps: providing a base which comprises a substrate part and fins bulged from the substrate; forming sacrificial layers on side walls of the fins and at the tops of the fins; forming a precursor isolating membrane between the adjacent fins on the substrate after the forming of the sacrificial layers, wherein the top of the precursor isolating membrane is higher than the tops of the fins; carrying out the annealing process of the precursor isolating membrane, and converting the precursor isolating membrane into an isolating membrane; removing a part of the isolating membrane, exposing the tops of the fins and a part of the side walls, and forming an isolated structure. According tothe invention, the sacrificial layers are formed on side walls of the fins and at the tops of the fins at first. The sacrificial layers are oxidized at first in the following process of forming the precursor isolating membrane, so the sacrificial layers can protect the fins during the forming of the precursor isolating membrane, and weakens or avoids the oxidation of the fins, thereby reducing oravoiding the impact on the size of the fins, and optimizing the electrical performances of a semiconductor device.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] With the development trend of high-density integrated circuits, the devices that make up the circuit are placed more closely in the chip to fit the available space of the chip. Correspondingly, the density of active devices per unit area of ​​the semiconductor substrate continues to increase, so effective insulation between devices becomes more important. [0003] Shallow Trench Isolation (STI) technology has a good isolation effect (for example: process isolation effect and electrical isolation effect), shallow trench isolation technology also has the ability to reduce the area occupied by the wafer surface and increase the integration of devices Etc. Therefore, with the reduction of the size of integrated circuits, shallow trench isolation structures are mainly used for isolation between active...

AI Technical Summary

Problems solved by technology

[0004] However, the formation process of the isolation structure in the prior art is likely to adversely affect the electrical performance of the semiconductor device

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