Groove MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) device and making method thereof

Abstract

The invention discloses a groove MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) structure and a making method. In the structure, the depth of a gate contacting with a groove in a groove gate is smaller than that of a source body contacting with the groove in a body region. The groove MOSFET is adopted to efficiently prevent short circuit between the gate and drain caused by over etching of the gate contacting with the groove.

Description

technical field [0001] The invention mainly relates to a unit structure and a manufacturing method of a semiconductor power device. In particular, it relates to an improved trench MOSFET (Metal Oxide Semiconductor Field Effect Transistor) structure and its novel manufacturing method, so that the trench MOSFET structure can avoid gate-drain short circuit. Background technique [0002] An N-channel trench MOSFET device using a trench-type gate contact region and a trench-type source-body contact region in the prior art is shown in FIG. 1A . The structure of the N-channel trench MOSFET includes: a substrate 100 of N+ conductivity type; an epitaxial layer 102 of N conductivity type; a P-type body region 106; an N+ source region 108; a plurality of trench gates 110 located in the active region and At least one trench gate 110' for gate contact, the trench gates 110 and 110' are filled with polysilicon; source metal 112; gate metal 112'; trenched source-body contact region 114; t...

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Problems solved by technology

Especially in the trench MOSFET whose trench gate depth is less than 1.0 μm, the above phenomenon can easily lead to the occurrence of over-etching, that is, the deeper gate contact trench will pass through the trench gate 110 ′ and extend into the epitaxial layer 102, thereby resulting in a gate-drain short circuit, as shown in Figure 1B

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