Abstract: A semiconductor structure and a forming method thereof are provided. The forming method includes: providing a semiconductor substrate including a source region and a drain region spaced apart; and forming a gate oxide layer, an interface layer and a gate layer on one side of the semiconductor substrate. The gate oxide layer, the interface layer and the gate layer are all disposed between the source region and the drain region. The interface layer is disposed on one side of the gate oxide layer facing away from the semiconductor substrate. The gate layer is disposed on one side of the interface layer facing away from the gate oxide layer. The area of orthographic projection of the interface layer on the semiconductor substrate is smaller than the area of orthographic projection of the gate oxide layer on the semiconductor substrate.