Super long channel device within VFET architecture
Embodiments are directed to methods and resulting structures for a vertical field effect transistor (VFET) having a super long channel. A pair of semiconductor fins is formed on a substrate. A semiconductor pillar is formed between the semiconductor fins on the substrate. A region that extends under all of the semiconductor fins and under part of the semiconductor pillar is doped. A conductive gate is formed over a channel region of the semiconductor fins and the semiconductor pillar. A surface of the semiconductor pillar serves as an extended channel region when the gate is active.
1. A method for forming a semiconductor device, the method comprising:
forming a pair of semiconductor fins on a substrate;
forming a semiconductor pillar between the semiconductor fins on the substrate;
forming a bottom doped region that extends under all of the semiconductor fins and under part of the semiconductor pillar;
recessing the semiconductor pillar below a surface of the semiconductor fins; and
forming a conductive gate over a channel region of the semiconductor fins and the semiconductor pillar.
2. The method of claim 1 further comprising doping the semiconductor pillar.
3. The method of claim 1 further comprising forming a thick oxide layer between the conductive gate and the semiconductor fins and the semiconductor pillar.
4. The method of claim 1 further comprising forming a bottom spacer between the conductive gate and the bottom doped region.
5. The method of claim 1 further comprising forming a top spacer on the conductive gate.
6. The method of claim 1 further comprising forming top doped regions on exposed surfaces of the semiconductor fins.
7. The method of claim 6 further comprising forming a conductive contact on the top doped regions.
8. The method of claim 7 further comprising forming a gate contact on the conductive gate and over the semiconductor pillar.
9. The method of claim 1 , wherein a thickness of the semiconductor pillar is larger than a thickness of the semiconductor fins.