Patent ID: 8742492

Claim:
A device, the device comprising: a wafer substrate; a conical frustum structure formed in the wafer substrate, wherein the conical frustum structure includes a drain formed at a bottom portion of the conical frustum, a source formed at a top portion of the vertical conical frustum, and a channel formed at a middle portion of the conical frustum connecting the source and the drain; and a gate all-around (GAA) structure circumscribing the middle portion of the conical frustum structure, wherein the GAA structure overlaps with the source at one side of the GAA structure, crosses over the channel, and overlaps with the drain at another side of the GAA structure, the GAA structure including an interfacial layer (IL) and a metal gate layer deposited over the IL, and a poly gate layer deposited over the metal gate layer of the GAA structure.