Capacitors based on 10 nm antiferroelectric silicon-doped hafnium oxide (Si:HfO2) thin films are investigated in terms of energy storage efficiency, cycling endurance, and reliability. Atomic layer deposition (ALD) on an area-enhanced substrate with large-scale arrays of deep-trench structures is used to significantly increase the energy density, yielding a value of 450 μJ/cm2 and an energy storage efficiency of 67% at a voltage of 3 V. High breakdown fields are obtained, and the reliability measurement indicates that more than 90% of the devices survive three years when subjected to an operating voltage of 3 V. The film stoichiometry is optimized in terms of energy storage properties to achieve an antiferroelectric-like hysteresis loop with low fatigue during electric field cycling and uniform electrical characteristics throughout the 300 mm wafer. Si:HfO2 is a promising material for novel integrated energy storage applications, as it combines CMOS compatible manufacturing, high scalability, and conformal deposition using ALD.
High-density energy storage in Si-doped hafnium oxide thin films on area-enhanced substrates
Kati Kühnel, Malte Czernohorsky, Clemens Mart, Wenke Weinreich; High-density energy storage in Si-doped hafnium oxide thin films on area-enhanced substrates. J. Vac. Sci. Technol. B 1 March 2019; 37 (2): 021401. https://doi.org/10.1116/1.5060738
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