Transistor preparation method and transistor

The invention provides a preparation method of a transistor. The preparation method comprises the steps of providing a semiconductor substrate; sequentially forming an oxide dielectric layer, a high-K dielectric layer and a virtual gate on the semiconductor substrate in a stacking manner; forming a groove in the semiconductor substrate, and forming a source electrode and a drain electrode in the groove; forming an interlayer dielectric layer covering the semiconductor substrate and the virtual gate; forming a through hole which is respectively aligned with the source electrode and the drain electrode and a groove-shaped hole which is aligned with the virtual grid electrode in the interlayer dielectric layer, and removing the virtual grid electrode in the process of forming the groove-shaped hole; and forming a conductive metal material in the groove-shaped hole and the through hole. The invention also provides a transistor prepared by using the method. According to the preparation method of the transistor, th