FeFET-Based Content-Addressable Storage Class Memory: Device Variation
and High-Temperature Compatibility
Abstract
Hafnium oxide (HfO2)-based ferroelectric field effect transistors
(FeFETs) have revolutionized the emerging non-volatile memory
area, especially with the potential to replace flash memories for
several applications. In this article, we investigate the suitability of
FeFETs memories, especially FeFET-based content addressable memory
(CAM)-cells, as storage class memory under junction temperature
variations. FeFETs with silicon oxynitride interfacial layer have been
fabricated and characterized at various temperatures, varying from room
temperature to 120◦C. Although the memory window, numbers of
programmable states, and endurance deteriorate at high temperatures,
FeFETs show excellent robustness in data retention, write latency, and
read stability at all temperatures, especially for binary operation.
Finally, system SPICE simulations using experimental data were conducted
to gauge the robustness of the data-search operation using the CAM array
under different temperatures. Despite temperature-variation-induced
changes in FeFET devices, we have observed that binary CAM cells perform
robust and unerring search operations for storing and searching data at
temperatures up to 120 °C.