Preparation method for semiconductor device

A method for manufacturing a semiconductor device, the semiconductor device comprising a work structure and a protection structure configured to protect the work structure, the method comprising:

• providing a semiconductor substrate comprising a cell region and a non-cell region, forming an isolation dielectric layer on the non-cell region of the semiconductor substrate, and forming a semiconductor layer having a first-conductivity-type doping on the isolation dielectric layer;
• performing a first-conductivity-type well implantation to the semiconductor substrate by using the semiconductor layer and the isolation dielectric layer as masks, and forming a well region in the cell region of the semiconductor substrate;
• doping the well region to form the work structure in the cell region, and doping the semiconductor layer to form the protection structure on the non-cell region;
• and
• forming an interlayer dielectric layer on the work structure and the protection structure, forming a contact hole in the interlayer dielectric layer, forming a metal interconnection layer connected to the contact hole on the interlayer dielectric layer, the work structure and the protection structure being connected by the metal interconnection layer and the contact hole.