US Patent 11075280 Self-aligned gate and junction for VTFET

Self-aligned gate/junction for VTFET devices are provided. In one aspect, a method of forming a VTFET device includes: forming a stack on a wafer including a first c-SiGe layer, a c-Si layer, and a second c-SiGe layer, wherein the first c-SiGe layer serves as a bottom source/drain; forming fin hardmasks on the stack; partially recessing the second c-SiGe layer to form a fin(s) in the second c-SiGe layer, wherein the second c-SiGe layer that is partially recessed/fin(s) serve as a top source/drain; amorphizing the c-Si layer to form a-Si regions in between c-Si regions that serve as vertical channels; selectively removing the a-Si regions to form gate trenches; forming bottom/top spacers in the gate trenches; and forming gates in the gate trenches that are offset from the bottom/top source/drain by the bottom/top spacers. A VTFET device is also provided. The VTFET device is suitable for 3D monolithic integrated circuits.