Complementary tunneling field effect transistor and method for forming the same

A method for forming a complementary tunneling field effect transistor, comprising steps of:

• providing a substrate;
• forming an insulating layer on the substrate;
• forming a semiconductor layer on the insulating layer and doping the semiconductor layer to form a first doped region and a second doped region;
• forming a third semiconductor layer on the semiconductor layer;
• etching a part of the third semiconductor layer and a part of the semiconductor layer to form a hollow U-shaped concave;
• forming a U-shaped gate structure in the U-shaped concave;
• forming a first type TFET vertical structure and a second type TFET vertical structure on two sides of the U-shaped gate structure respectively;
• etching the semiconductor layer to expose a second part of the first doped region and a second part of the second doped region, in which the second part of the first doped region and the second part of the second doped region are under a bottom of the U-shaped concave, the second part of the first doped region is connected with the second part of the second doped region and a connecting portion between the second part of the first doped region and the second part of the second doped region is used as a drain output of the complementary tunneling field effect transistor.