STI SILICON NITRIDE CAP FOR FLAT FEOL TOPOLOGY

• Main Authors: JAKUBOWSKI FRANK, RADECKER JOERG S, BAARS PETER
• Format: Patent
• Language: English
• Published: 26.07.2012
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Transistor devices are formed with a nitride cap over STI regions during FEOL processing. Embodiments include forming a pad oxide layer on a substrate, forming an STI region in the substrate so that the top surface is level with the top surface of the pad oxide, forming a nitride cap on the STI region and on a portion of the pad oxide layer on each side of the STI region, implanting a dopant into the substrate, deglazing the nitride cap and pad oxide layer, removing the nitride cap, and removing the pad oxide layer. Embodiments include forming a silicon germanium channel (c-SiGe) in the substrate prior to deglazing the pad oxide layer. The nitride cap protects the STI regions and immediately adjacent area during processes that tend to degrade the STI oxide, thereby providing a substantially divot free substrate and an STI region with a zero step height for the subsequently deposited high-k dielectric and metal electrode.