Shield gate trench field effect transistor and preparation method thereof

A technology of field effect transistors and shielding gates, which is applied in the direction of transistors, semiconductor/solid-state device manufacturing, semiconductor devices, etc., can solve problems such as the reduction of field effect transistor parameter characteristics, achieve the effect of easy manufacturing process and improve reverse withstand voltage capability

CN113035715AActive Publication Date: 2021-06-25CHINA RESOURCES MICROELECTRONICS (CHONGQING) CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2021-06-25

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Abstract

The invention provides a shield gate trench field effect transistor and a preparation method thereof. The method mainly comprises the steps: providing a substrate, forming an epitaxial layer on the upper surface of the substrate, forming a deep trench in the epitaxial layer, and forming a shielding oxide layer, shield polysilicon, a first isolation oxide layer and a second isolation oxide layer on the inner wall of the deep trench, wherein the density of the first isolation oxide layer is greater than that of the second isolation oxide layer; removing the second isolation oxide layer, a part of the first isolation oxide layer and the shielding oxide layer through wet etching, so that an obtuse angle is formed between the upper surface of the shielding oxide layer and the side wall of the deep trench; forming a gate oxide layer and gate polysilicon on the inner wall of the deep trench; and forming other structures of the field effect transistor. According to the method, the reverse voltage endurance capability of the gate oxide layer can be effectively improved, and other working parameters of the field effect transistor cannot be influenced; and the preparation method provided by the invention is easy to realize in process manufacturing and mass production.
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Description

technical field

[0001] The invention belongs to the field of design and manufacture of semiconductor devices, in particular to a shielded gate trench field effect transistor and a preparation method thereof. Background technique

[0002] With the continuous development of semiconductor technology, the structure of metal oxide semiconductor field effect transistor (MOSFET) has also been continuously improved. Shielded gate trench field effect transistor (Trench Split Gate MOSFET) is one of the improved structures. Its main feature is to increase the shielded gate structure on the basis of traditional trench MOSFET to achieve better switching characteristics and higher source-to-drain strike. breakdown voltage, lower on-resistance and lower power consumption. Due to these advantages, trench shielded gate MOS devices are widely used in various power electronic systems.

[0003] In the traditional power device structure, the gate withstand voltage of the MOS transistor is rela...

Examples

Embodiment Construction

[0050] Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

[0051] see Figure 1 to Figure 9. It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of ​​the present invention, so that only the components related to the present invention are shown in the diagrams rather than the number, shape and Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component...