MOSFET and method for manufacturing the same
The present disclosure discloses a metal-oxide-semiconductor field-effect transistor (MOSFET) and a method for manufacturing the same. The MOSFET includes: a silicon on insulator (SOI) wafer which comprises a semiconductor substrate, a buried insulating layer, and a semiconductor layer, the buried insulating layer being on the semiconductor substrate, and the semiconductor layer being on the buried insulating layer; a gate stack on the semiconductor layer; a source region and a drain region, which are in the semiconductor layer and on opposite sides of the gate stack; and a channel region, which is in the semiconductor layer and sandwiched by the source region and the drain region, wherein the MOSFET further comprises a back gate, the back gate being located in the semiconductor substrate and having a first doped region in a lower portion of the back gate and a second doped region in an upper portion of the back gate.
1. A Metal Oxide Semiconductor Field Effect Transistor (MOSFET), comprising:
a Semiconductor on Insulator (SOI) wafer, which comprises a semiconductor substrate, a buried insulating layer, and a semiconductor layer, the buried insulating layer being on the semiconductor substrate, and the semiconductor layer being on the buried insulating layer;
a gate stack on the semiconductor layer;
a source region and a drain region, which are in the semiconductor layer and on opposite sides of the gate stack; and
a channel region, which is in the semiconductor layer and sandwiched by the source region and the drain region,
wherein the MOSFET further comprises a back gate located in the semiconductor substrate, the back gate having a first doped region in a lower portion of the back gate with a first doping type, a second doped region in an upper portion of the back gate with the first doping type, and an anti-doped region below the channel region and in the second doped region with a second doping type, wherein the doping concentration of the second doped region of the back gate decreases gradually in a direction from either the source region or the drain region towards the center of the channel region, and wherein the anti-doped region has a doping concentration lower than a doping concentration of the second doped region of the back gate.
2. The MOSFET according to claim 1 , wherein the first doping type of the back gate is the same as or opposite to a doping type of the MOSFET.
3. The MOSFET according to claim 1 , wherein the doping concentration of the back gate is about 1×10 17 cm −3 to about 1×10 20 cm −3 .
4. The MOSFET according to claim 1 , wherein the back gate adjoins the buried insulating layer.
5. The MOSFET according to claim 1 , wherein the second doping type is opposite to the first doping type.
6. The MOSFET according to claim 1 , wherein the doping concentration of the anti-doped region is about 1×10 15 cm −3 to about 1×10 18 cm −3 .