Metal oxide semiconductor field effect transistor having asymmetric lightly doped drain regions

摘要

A metal-oxide-semiconductor field effect transistor (MOSFET) includes a substrate and a gate structure over a top surface of the substrate. The MOSFET further includes a source in the substrate on a first side of the gate structure and a drain in the substrate on a second side of the gate structure opposite the first side. A surface portion of the substrate extending from the source to the drain has an asymmetric dopant concentration profile.

主权项

1. A metal-oxide-semiconductor field effect transistor (MOSFET) comprising:
a substrate; a gate structure over a top surface of the substrate, wherein the gate structure has a gate dielectric layer over the top surface of the substrate; a source in the substrate on a first side of the gate structure, wherein a first dopant concentration is between the source and a region under the gate dielectric layer, and a depth of the first dopant concentration is shallower than a depth of the source; a drain in the substrate on a second side of the gate structure opposite the first side, wherein a second dopant concentration is between the drain and the region under the gate dielectric layer, and the second dopant concentration is less than the first dopant concentration; and a deep well in the substrate extending under the source, the gate structure and the drain.