Fabrication and device characterization of alternative gate stacks using the non self-aligned gate process.

摘要

In order to improve MOSFET transistor performance, aggressive scaling of devices has continued. As lateral device dimensions continue to scale down, gate oxide thicknesses must also be scaled down. According to the 2001 International Technology Roadmap for Semiconductor (ITRS) for sub-micron technology, an equivalent oxide thickness (EOT) less than 1.0 nm is required for high performance devices. However, at this thickness SiO₂ has reached its scaling limit due to the high tunneling current, especially in low power devices. The use of high K dielectrics may circumvent this impediment since physically thicker dielectrics can be used to reduce gate leakage while maintaining the same level of inversion charge. In this study, we used an alternative, non self-aligned gate process to fabricate both NMOS and PMOS devices with a variety of high K gate dielectric and metal gate electrode materials; finally their electrical properties were characterized.