Phase-Change Heterostructures and Nanocomposites for Low-Power Computing

Today’s nanoelectronics systems are reaching the limits of energy and latency for numerous data-intensive applications. Among the existing non-volatile memory technologies, phase-change memory (PCM) holds promise for high-density storage [1]. However, this technology must achieve low-power and stable operation at nanoscale dimensions to be useful in heterogeneously integrated logic and memory. This talk will delve into our recent efforts on the atomic-scale interface and electro-thermal engineering of new phase-change materials for low-power and brain-inspired computing.<br/>Using a combination of phase-change heterostructures and nanocomposites, we have demonstrated sub-1 picojoule switching energy and sub-1 V switching voltage in nanoscale PCM devices [2,3], which are promising for on-chip logic and memory integration. These devices also show low resistance drift, good endurance, fast switching (40 ns), and a large on-off ratio (&gt;100) [1, 2]. The energy-efficient switching is enabled by strong heat confinement within the superlattice material interfaces [3,4]. The heat confinement is further amplified in low-thermal conductivity flexible polyimide substrates, a new paradigm in low-power memory for flexible electronics [5]. We also demonstrate that the material and thermal properties of the heterostructures are controlled by the interface density, which ultimately plays a crucial role in regulating the device performance [6,7]. Additionally, phase-change nanocomposites facilitate the fast-switching speed and gradual bi-directional conductance change in PCM devices, favorable for low-power spiking neural networks [8,9]. These results demonstrate the promise of novel heterostructures and their interface-driven transport modulation for low-power and high-density neuro-inspired memory.<br/><b>References:</b><br/>[1] S. Raoux, E. Pop <i>et al</i>., MRS Bulletin 39, 703-710 (2014). [2] X. Wu, A.I. Khan, E Pop <i>et al</i>., Nature Commun. 15, 13 (2024). [3] A.I. Khan, E. Pop <i>et al</i>., IEEE Electron Dev. Lett. 43, 204-207 (2022). [4] H. Kwon, A.I. Khan, E. Pop, K.E. Goodson <i>et al</i>., Nano Letters 21, 5984–5990 (2021) [5] A.I. Khan, E. Pop <i>et al</i>., Science 373, 1243-1247 (2021). [6] A.I. Khan, E. Pop <i>et al</i>., Nano Letters 22, 6285–6291 (2022). [7] J. Zhao, A.I. Khan, E. Pop, L. Allen <i>et al</i>., Nano Letters 23, 4587-4594 (2023). [8] A.I. Khan, E. Pop <i>et al.,</i> Adv. Materials 35, 2300107 (2023). [9] S.B. Hamid, A.I. Khan, E. Pop <i>et al</i>., IEEE DRC (2024).