| 主权项 |
1. A method for forming a field effect transistor (FET), the method comprising:
providing a substrate; etching the substrate to form a protrusion on a surface of the substrate; forming isolation features on the substrate; doping a portion of the substrate adjacent to the protrusion to form a drain region between the isolation features, including doping a lower portion of the protrusion to form a raised drain region; forming a first isolation dielectric layer over the drain region; forming a gate stack having a planar portion over the drain region, which is parallel to the surface of the substrate and has a sidewall and a gating surface, which wraps around a middle portion of the protrusion and which overlaps with the raised drain region; forming a second isolation dielectric layer over the planar portion of the gate stack and the raised drain region; recessing a portion of the gating surface of the gate stack to expose a top portion of the protrusion; forming a source region on the top portion of the protrusion with a different doping type than the drain region, the source region overlapping with the gating surface of the gate stack; forming a third isolation dielectric layer over the source region, the gate stack and the second isolation dielectric layer; forming a drain contact on the drain region and a portion of one of the isolation features together; and simultaneously with the drain contact formation, forming a gate contact on the planar portion of the gate stack and the sidewall of the planar portion of the gate stack, the gate contact extending through a portion of the isolation dielectric layer, and forming a source contact on the source region. |
