Multifunctional 2D FETs exploiting incipient ferroelectricity in freestanding SrTiO3 nanomembranes at sub-ambient temperatures
Dipanjan Sen, Harikrishnan Ravichandran, M.B. Das, Pranavram Venkatram, Sooho Choo, Shivasheesh Varshney, Zhiyu Zhang, Yongwen Sun, Jay Shah, Shiva Subbulakshmi Radhakrishnan, Akash Saha, Sankalpa Hazra, Chen Chen, Joan M. Redwing, K. Andre Mkhoyan, Venkatraman Gopalan, Yang Yang, Bharat Jalan, Saptarshi Das
Abstract
Incipient ferroelectricity bridges traditional dielectrics and true ferroelectrics, enabling advanced electronic and memory devices. Firstly, we report incipient ferroelectricity in freestanding SrTiO3 nanomembranes integrated with monolayer MoS2 to create multifunctional devices, demonstrating stable ferroelectric order at low temperatures for cryogenic memory devices. Our observation includes ultra-fast polarization switching (~10 ns), low switching voltage (<6 V), over 10 years of nonvolatile retention, 100,000 endurance cycles, and 32 conductance states (5-bit memory) in SrTiO3-gated MoS2 transistors at 15 K and up to 100 K. Additionally, we exploit room-temperature weak polarization switching, a feature of incipient ferroelectricity, to construct a physical reservoir for pattern recognition. Our results showcase the potential of utilizing perovskite material properties enabled by advancements in freestanding film growth and heterogeneous integration, for diverse functional applications. Notably, the low 180 °C thermal budget for fabricating the 3D-SrTiO3/2D-MoS2 device stack enables the integration of diverse materials into silicon complementary metal-oxide-semiconductor technology, addressing challenges in compute-in-memory and neuromorphic applications. Sen et al. report the stacking of a perovskite incipient ferroelectric nanomembrane with atomically thin 2D material for a back-end-of-line compatible ferroelectric-like field effect transistors, functioning as a cryogenic memory at 15 K and as an inference engine at room temperature.