Raised Epitaxial LDD in MuGFETs and Methods for Forming the Same

• Main Authors: Chen, Hou-Yu, Yang, Shyh-Horng, Lu, Yong-Yan
• Format: Patent
• Language: English
• Published: 18.03.2021
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Embodiments include Multiple Gate Field-Effect Transistors (MuGFETs) and methods of forming them. In an embodiment, a structure includes a substrate, a fin, masking dielectric layer portions, and a raised epitaxial lightly doped source/drain (LDD) region. The substrate includes the fin. The masking dielectric layer portions are along sidewalls of the fin. An upper portion of the fin protrudes from the masking dielectric layer portions. A first spacer is along a sidewall of a gate structure over a channel region of the fin. A second spacer is along the first spacer. The raised epitaxial LDD region is on the upper portion of the fin, and the raised epitaxial LDD region adjoins a sidewall of the first spacer and is disposed under the second spacer. The raised epitaxial LDD region extends from the upper portion of the fin in at least two laterally opposed directions and a vertical direction.