Trench silicon carbide MOSFET device and preparation method thereof

The invention discloses a trench silicon carbide MOSFET device and a preparation method thereof. The trench silicon carbide MOSFET device comprises an N-epitaxial layer, at least two P+ type injection regions suspended in the N-epitaxial layer, and a trench gate structure with two bottom corners respectively contacted with the two P+ type injection regions. Particularly, the electric field intensity of the oxide layer at the bottom and the side surface of the gate groove is effectively reduced, and the reliability of the gate oxide is improved; a depletion region is formed when the floating type P-type buried layer is reversely blocked, so that the reverse voltage withstanding characteristic of the device is obviously improved; the gate-drain contact area is reduced, the gate-drain capacitance is reduced, and the switching rate is improved. 本发明公开一种沟槽碳化硅MOSFET器件及其制备方法，该沟槽碳化硅MOSFET器件包括：N-外延层；至少两个P+型注入区，悬浮设置于N-外延层内；沟槽栅结构，沟槽栅结构的两个底角分别与两个P+型注入区接触。增强了栅氧的可靠性，特别有效降低栅槽底部和侧面氧化层的电场强度，提高栅氧可靠性；浮空式P型埋层反向阻断时形成耗尽区，使器件的反向耐压特性