Collaborative: Mixed Anion and Cation Based Transistor Architecture for Ultra-Low Power Complementary Logic Applications

Research objectives and approaches: The objective of this research is materials, device and circuit based co-exploration of mixed-anion and mixed-cation compound semiconductor based transistors for energy-efficient computing. The approach is a) experimental investigation of n-channel mixed anion (InAsxSb1-x) quantum-well transistors and p-channel mixed cation (InyGa1-ySb) transistors to address dynamic power consumption in complementary logic and RF circuits; b) experimental investigation of mixed-anion and cation based tunnel transistors to address stand-by power consumption in logic and embedded memory circuits, and c) development of design toolkit to enable heterogeneous circuit implementation with emerging devices. Intellectual merit: The key scientific merits of this proposal are: i) Harnessing the excellent electron and hole transport properties in mixed-anion and mixed-cation antimonide material system to provide ultra-low power transistor solutions. We investigate mixed-anion material, InAsxSb1-x with varying As and Sb mole fraction, to achieve high electron mobility (>13,000 cm2V-1s-1) to demonstrate n-channel quantum-well FETs (QWFETs). We explore mixed-cation materials, InyGa1-ySb to maximize hole mobility (>2,000 cm2V-1s-1) by varying In and Ga mole fractions to enable band-gap engineered p-channel QWFETs; Device layer design is done with the primary goal of achieving a common high-k dielectric gate solution for both n-channel and p-channel QWFETs; ii) Harnessing the availability and tunability of staggered band-edge lineup in the mixed anion-cation antimonide material system to explore tunnel transistor (TFET) architecture with steep switching characteristics to address stand-by energy consumption; iii) Exploration of a heterogeneous system via implementation of speed critical, high activity logic circuits using QWFETs and low activity factor circuits using Tunnel FETs. This investigation will expand our fundamental understanding of the material science of mixed-anion and mixed-cation based material systems, novel QWFET and TFET device configurations and implementation of energy efficient logic elements, interconnect fabric and embedded memory. Broader Impact: The proposed research directly addresses the quest in the semiconductor industry for longer term solutions to technology scaling and addressing energy efficiency. The outcome of this research will have a direct impact on the future of ?green? nanoelectronics and many-core processor architecture design. A broader impact of successful development of the underlying materials, novel device architectures and energy efficient circuits with several orders of magnitude reduced energy consumption than today?s available electronics can usher in a new generation of implantable medical electronics needed for health monitoring and nanomedicine applications. Throughout the project, the key results will be disseminated via a dedicated WIKI web portal and via existing Penn State MRSEC-related outreach channels.