Preparation method of SGT-MOSFET semiconductor device

The invention provides a preparation method of an SGT-MOSFET semiconductor device, and the method comprises the steps: forming an initial first sacrificial layer on a semiconductor substrate, and enabling the initial first sacrificial layer to cover the side wall and the bottom of a deep groove; and performing ion implantation on the initial first sacrificial layer by adopting an implantation process, and forming a first sacrificial layer covering the side wall and the bottom of the deep trench and a second sacrificial layer located on the first sacrificial layer on the semiconductor substrate. Ion implantation is carried out on an initial first sacrificial layer on the side wall of a deep trench, a first sacrificial layer covering the side wall and the bottom of the deep trench and a second sacrificial layer located on the first sacrificial layer are formed on a semiconductor substrate, and the compactness of the second sacrificial layer is lower than that of the first sacrificial layer. Therefore, the longi