Semiconductor devices and methods for forming semiconductor devices
A semiconductor device is proposed. The semiconductor device includes a source region of a field effect transistor having a first conductivity type, a body region of the field effect transistor having a second conductivity type, and a drain region of the field effect transistor having the first conductivity type. The source region, the drain region, and the body region are located in a semiconductor substrate of the semiconductor device and the body region is located between the source region and the drain region. The drain region extends from the body region through a buried portion of the drain region to a drain contact portion of the drain region located at a surface of the semiconductor substrate, the buried portion of the drain region is located beneath a spacer doping region, and the spacer doping region is located within the semiconductor substrate.
1. A semiconductor device comprising:
a source region of a field effect transistor of the semiconductor device having a first conductivity type;
a body region of the field effect transistor having a second conductivity type; and
a drain region of the field effect transistor having the first conductivity type and having a buried portion,
wherein the source region, the drain region, and the body region are located in a semiconductor substrate of the semiconductor device, wherein the source region is embedded in the body region,
wherein at least a part of the body region is located between the source region and the drain region,
wherein the drain region extends from the body region to a drain contact interface between a drain contact portion of the drain region and a drain wiring structure located at a surface of the semiconductor substrate,
wherein a gate of the field effect transistor is located laterally between the source region and a spacer doping region and does not overlap the spacer doping region along a vertical direction,
wherein the gate is configured to control a transistor channel through the body region enabling a current path of the field effect transistor extending from the source region through the body region and through the buried portion to the drain contact portion,
wherein the buried portion of the drain region is located directly beneath the spacer doping region, wherein the spacer doping region is located within the semiconductor substrate,
wherein the spacer doping region and the body region are respective portions of a well doping region having the second conductivity type.
2. The semiconductor device according to claim 1 , wherein the spacer doping region extends vertically from the surface of the semiconductor substrate to the buried portion of the drain region.
3. The semiconductor device according to claim 1 , wherein a portion of the drain region located adjacent to the body region is separated from the drain contact portion by the spacer doping region at the surface of the semiconductor substrate.
4. The semiconductor device according to claim 1 , wherein a length of a shortest current path between the transistor channel of the field effect transistor and the drain contact interface between the drain contact portion of the drain region and the drain wiring structure is at least 1.5 times a minimal distance between the body region and the drain contact interface.
5. The semiconductor device according to claim 1 , wherein the drain region is U-shaped in a vertical cross-section of the semiconductor substrate.
6. The semiconductor device according to claim 5 , wherein the spacer doping region is located between two legs of the U-shaped drain region.
7. The semiconductor device according to claim 1 , wherein a vertical extension of the spacer doping region is at least 300 nm.
8. The semiconductor device according to claim 4 , wherein a distance between the body region and the drain contact interface is at most 500 nm.
9. The semiconductor device according to claim 1 , wherein a minimal lateral extension of the spacer doping region is at least 200 nm and/or at most 3000 nm.
10. The semiconductor device according to claim 1 , wherein the buried portion is a portion of a deep well doping region of the first conductivity type.
11. The semiconductor device according to claim 10 , wherein the deep well doping region extends deeper into the semiconductor substrate than the well doping region.
12. The semiconductor device according to claim 1 , wherein an average net doping concentration of the spacer doping region differs from an average net doping concentration of the body region by at most 10% of the average net doping concentration of the body region.
13. The semiconductor device according to claim 1 , wherein the field effect transistor is a fin field effect transistor having an at least one fin.
14. The semiconductor device according to claim 13 , wherein an average width of the at least one fin of the fin field effect transistor is at least 10 nm.
15. The semiconductor device according to claim 1 , wherein a breakdown voltage of the field effect transistor is higher than 8V.
16. A method for forming a semiconductor device, the method comprising:
forming a drain region of a field effect transistor of the semiconductor device having a first conductivity type and having a buried portion;
forming a body region of the field effect transistor having a second conductivity type; and
forming a source region of the field effect transistor having the first conductivity type,
wherein the source region, the drain region, and the body region are positioned in a semiconductor substrate of the semiconductor device, wherein the source region is embedded in the body region, wherein the body region is positioned between the source region and the drain region,
wherein the drain region extends from the body region to a drain contact interface between a drain contact portion of the drain region and a drain wiring structure positioned at a surface of the semiconductor substrate,
wherein a gate of the field effect transistor is located laterally between the source region and a spacer doping region and does not overlap the spacer doping region along a vertical direction,
wherein the gate is configured to control a transistor channel through the body region enabling a current path of the field effect transistor extending from the source region through the body region and through the buried portion to the drain contact portion,
wherein the buried portion of the drain region is positioned directly beneath the spacer doping region, wherein the spacer doping region is positioned within the semiconductor substrate,
wherein the spacer doping region and the body region are respective portions of a well doping region having the second conductivity type.
17. The method according to claim 16 , wherein a length of a shortest current path between the body region and the drain contact interface between the drain contact portion of the drain region and the drain wiring structure is at least 1.5 times a minimal distance between the body region and the drain contact interface.
18. A semiconductor device comprising:
a source region of a fin field effect transistor of the semiconductor device having a first conductivity type;
a body region of the fin field effect transistor having a second conductivity type; and
a drain region of the fin field effect transistor having the first conductivity type and having a buried portion,
wherein the source region, the drain region, and the body region are located in a semiconductor substrate of the semiconductor device, wherein the source region is embedded in the body region,
wherein at least a part of the body region is located between the source region and the drain region,
wherein the drain region extends from the body region to a drain contact interface between a drain contact portion of the drain region and a drain wiring structure located at a surface of the semiconductor substrate,
wherein a gate of the fin field effect transistor is located laterally between the source region and a spacer doping region and does not overlap the spacer doping region along a vertical direction,
wherein the gate is configured to control a transistor channel through the body region enabling a current path of the fin field effect transistor extending from the source region through the body region and through the buried portion to the drain contact portion,
wherein the buried portion of the drain region is located directly beneath the spacer doping region, wherein the spacer doping region is located within the semiconductor substrate outside a fin of the fin field effect transistor,
wherein the spacer doping region and the body region are respective portions of a well doping region having the second conductivity type.