Single Atomic Layer Ferroelectric on Silicon

A single atomic layer of ZrO₂ exhibits ferroelectric switching behavior when grown with an atomically abrupt interface on silicon. Hysteresis in capacitance–voltage measurements of a ZrO₂ gate stack demonstrate that a reversible polarization of the ZrO₂ interface structure couples to the carriers in the silicon. First-principles computations confirm the existence of multiple stable polarization states and the energy shift in the semiconductor electron states that result from switching between these states. This monolayer ferroelectric represents a new class of materials for achieving devices that transcend conventional complementary metal oxide semiconductor (CMOS) technology. Significantly, a single atomic layer ferroelectric allows for more aggressively scaled devices than bulk ferroelectrics, which currently need to be thicker than 5–10 nm to exhibit significant hysteretic behavior (Park, et al. Adv. Mater. 2015, 27, 1811).