The design of more efficient processors is a major driving force of the computing industry. Over multiple decades, reducing the size of transistors, which are the building blocks of microprocessors, has been the main driver for efficiency improvements. With this trend of transistor shrinking nearing the physical limit, this research explores three-dimensional chips, where transistors are stacked in multiple layers, as an alternate approach to enhance efficiency. A major challenge with three-dimensional chips is the large dimension of the connections compared to the transistor itself. This project will leverage a new technology called monolithic three-dimensional design (M3D), where inter-layer connections are of dimensions similar to that of a transistor. This research will result in new M3D-based designs for microprocessors that reduce energy and time consumed in interconnections, and enable new functional features for microprocessors. The project will also enhance the national workforce development efforts by training undergraduate, graduate and underrepresented groups in a much-needed area of semiconductor electronics.
This project will involve synergistic exploration of process technology and M3D-based architectural design spaces of processors towards achieving transformational impact on processor and accelerator performance. The research will first develop a simulation infrastructure that enables systematic exploration of the space by varying the architectural and technology parameters. Leveraging the simulation infrastructure, this project will perform the following tasks: (1) evaluation of layer-wise partitioning of processor core and cache structures; (2) design of primitive compute functions for integration with the cache memories; (3) design of M3D-enabled application-specific accelerators; and (4) integration of heterogeneous memory technologies to provide support for power efficiency.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
