Manufacturing method of shield gate trench device

By optimizing the surface morphology of the isolation oxide layer in the shielded gate trench device and optimizing the bottom morphology of the control gate, the problem of sharp corners at the bottom of the control gate and the gate oxygen layer in the prior art is solved, which significantly enhances the BVGSS performance of the device.

CN119993830APending Publication Date: 2025-05-13WUXI CHINA RESOURCES HUAJING MICROELECTRONICS +1
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Patent Information

Application Number
CN202311441427.0
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2023-10-31
Publication Date
2025-05-13

AI Technical Summary

Technical Problem

In existing shielded gate trench devices, the corners at the bottom of the control gate are sharp, and small holes are easily generated when growing the gate oxygen layer, resulting in a decrease in the device gate breakdown voltage.

Method used

By forming a sacrificial oxide layer above the isolation oxide layer and etching the sacrificial oxide layer and the preset thickness isolation oxide layer, the surface morphology of the isolation oxide layer is optimized, so that its upper surface has an arc-shaped structure with an edge area higher than the center area, so as to avoid small holes at the corners when the gate oxygen layer is subsequently grown, and the bottom morphology of the control gate electrode is optimized to round the corners.

Benefits of technology

It effectively enhances the device's gate breakdown voltage (BVGSS) performance, avoids the emergence of weak areas in the gate oxygen layer, and improves the device's switching speed and dynamic loss performance.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention provides a manufacturing method of a shield gate trench device, which comprises the following steps: providing a substrate, forming a trench in the substrate, forming a shield gate in the trench, forming an isolation oxide layer above the shield gate, the isolation oxide layer being located in the trench, and the part of the trench above the isolation oxide layer forming a groove space; a sacrificial oxide layer is formed on the side wall and the bottom of the groove space, the sacrificial oxide layer and the preset isolation oxide layer are etched, and the upper surface of the isolation oxide layer after etching is of an arc-shaped structure with the edge area higher than the center area; and forming a gate oxide layer on the side wall of the groove space, and forming a control gate in the groove space. The upper surface of the isolation oxide layer is of the arc-shaped structure with the edge area higher than the center area, so that small holes cannot be generated at corners during subsequent growth of the gate oxide layer, the bottom morphology of the control gate is optimized, the corners of the bottom of the control gate are rounded, and the BVGSS performance is enhanced.
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