SHF:Small: Collaborative Research: Exploring 3-Dimensional Integration Strategies of STTRAM

The development of high-density memory is fueled by recent advancements in several critical areas ranging from big data analytics, Internet-of-Things (IoT), wearable electronics, smart phones, assistive devices, cybersecurity to weather tracking systems. Currently available conventional memory technologies face serious challenges in addressing these needs due to increased energy consumption, scalability limitations, and limited bandwidth. The objective of this proposal is to develop novel memory devices by enabling 3D integration of spin-torque transfer RAM devices (STTRAM) with appropriate selector diodes (SD). These type of memory devices will be massively scalable, energy-efficient, and fast which will open tremendous opportunities to integrate them in existing memory architectures to enable various futuristic applications. The project will integrate education by incorporating research outcomes in PI's academic courses. Industrial feedback will be sought via collaborations. Under-represented groups will be involved in science and engineering through several outreach programs at Penn State University (PSU) and University of Cincinnati (UC) such as Summer Research Opportunities Program (SROP) at PSU, and Emerging Ethnic Engineers (E3) program at UC which provides opportunities to the high-school students from the inner-city schools with economically challenged background to participate in internships and lab-experience activities. Undergraduate students will be involved in research via Research Experiences for Undergraduates (REU) program at both the universities. Dissemination of results will be accomplished by publications in high-impact scientific journals, conference presentations, and YouTube lecture videos.

The intellectual merit of the project is in understanding the integration compatibility of STTRAM devices with SD and developing highly scalable 3D crossbar arrays of memory technologies based on integrated STTRAM and SD. The objectives will be achieved by executing the following specific aims: (i) modeling and simulation of STTRAM-SD arrays, (ii) resilience analysis and optimization studies to minimize the impact of device-level variabilities on performance metrics, (iii) optimization of STTRAM-SD architectures for high-performance computing and IoT, (iv) designing, fabrication, testing, and modeling of novel SD devices based on energy band-engineered and doping-engineered transition metal oxide and electrode stacks, (v) designing and fabrication of small-size STTRAM-SD arrays, electrical testing and modeling to benchmark simulations and experimental results. It is anticipated that the successful completion of this project will lead to a fundamental understanding of the compatibility of STTRAM with SD and provide a platform-technology to develop high-density memories which will have transformative impact on commercializing and advancing the futuristic applications.