Junctionless transistor device and method for preparing the same

A junctionless transistor device, comprising:

• a semiconductor substrate having a surface;
• a channel disposed over the semiconductor substrate, wherein the channel comprises a first channel extending in a lateral direction substantially parallel to the surface of the semiconductor substrate, and a second channel extending in a vertical direction substantially perpendicular to the surface of the semiconductor substrate, wherein the first channel and the second channel are in contact at one end, and the channel has a first doping type;
• a first source/drain disposed over the semiconductor substrate, and in contact with the first channel, wherein the first source/drain has the first doping type;
• a second source/drain disposed over the second channel, and in contact with the second channel, wherein the second source/drain has the first doping type;
• a gate disposed over an upper surface of the first channel and side surfaces of the second channel, wherein the gate has a second doping type opposite to the first doping type;
• and
• a gate dielectric layer disposed between the gate and the channel.