Sub‐Thermionic Negative Capacitance Field Effect Transistors with Solution Combustion‐Derived Hf0.5Zr0.5O2

The fabrication of Hf0.5Zr0.5O2‐ferroelectric negative capacitor using solution combustion is presented for the first time. The starting materials used for the solution combustion to form equimolar Hf0.5Zr0.5O2 are to act as both combustible elements and cation sources. Jain's method, which is used for estimating the stoichiometric quantities of precursors in propellant chemistry, has also been modified and applied. The conventional assumption for this method that molecular oxygen does not take part in the reaction is refuted and stoichiometric combustion in the presence of molecular oxygen is proposed. This reaction is followed by post‐rapid thermal processing to stabilize the metastable, non‐centrosymmetric orthorhombic phase. The thin film stacks, Hf0.5Zr0.5O2/HfO2, are used to achieve sub‐thermionic swing (forward sweep: 25.42 ± 8.05 mV dec−1, reverse sweep: 42.56 ± 4.87 mV dec−1) in MoS2 negative capacitance field effect transistors with a hysteresis of ≈40 mV at 1 nA, resulting in ultra‐low‐power operation. To date, solution processing has only been utilized in simple circuits, and sensor arrays are far from commercialization. The present article opens a new avenue through improvements in the efficacy of solution‐processed ferroelectrics to realize ultra‐low‐power operation by switching below the thermionic limit (60 mV dec−1 at room temperature). The 2D‐MoS2 devices with ferroelectric‐Hf0.5Zr0.5O2/dielectric‐HfO2 negative capacitor show steep switching behavior.