This work looks at past, present, and future material changes for the metal-oxide-semiconductor field-effect transistor (MOSFET). It is shown that conventional planar bulk MOSFET channel length scaling, which has driven the industry for the last 40 years, is slowing. To continue Moore's law, new materials and structures are required. The first major material change to extend Moore's law is the use of SiGe at the 90-nm technology generation to incorporate significant levels of strain into the Si channel for 20%-50% mobility enhancement. For the next several logic technologies, MOSFETs will improve though higher levels of uniaxial process stress. After that, new materials that address MOSFET poly-Si gate depletion, gate thickness scaling, and alternate device structures (FinFET, tri-gate, or carbon nanotube) are possible technology directions. Which of these options are implemented depends on the magnitude of the performance benefit versus manufacturing complexity and cost. Finally, for future material changes targeted toward enhanced transistor performance, there are three key points: 1) performance enhancement options need to be scalable to future technology nodes; 2) new transistor features or structures that are not additive with current enhancement concepts may not be viable; and 3) improving external resistance appears more important than new channel materials (like carbon nanotubes) since the ratio of external to channel resistance is approaching 1 in nanoscale planar MOSFETs.
Index Terms-CMOS, metal-oxide-semiconductor field-effect transistor (MOSFET), new materials, strained silicon, very large scale integration (VLSI). Scott E. Thompson (S'87-M'87-SM'05) was an Intel Fellow, Director of Intel's 90-nm Logic Technology, and responsible for next generation process integration, transistor design, and technology yield from 1992 to 2004. He joined Intel in 1992 and worked on transistor design, circuit design, process integration, and yield on Intel's 0.35-, 0.25-, 0.18-, 0.13-, and 0.09-m advanced CMOS logic technologies. In 2004, he joined the University of Florida as an Associate Professor of electrical engineering. His current research interests include advanced transistors focusing on strained Si and Ge channel MOSFETs and carbon nanotube transistors.