High-<i>k</i> perovskite gate oxide for modulation beyond 10<sup>14</sup> cm<sup>-2</sup>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35302844.
- Also identified by DOI 10.1126/sciadv.abm3962 and PMC identifier 8932668.
- Licence recorded as CC BY-NC.
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Abstract
Scaling down of semiconductor devices requires high-<i>k</i> dielectric materials to continue lowering the operating voltage of field-effect transistors (FETs) and storing sufficient charge on a smaller area. Here, we investigate the dielectric properties of epitaxial BaHf<sub>0.6</sub>Ti<sub>0.4</sub>O<sub>3</sub> (BHTO), an alloy of perovskite oxide barium hafnate (BaHfO<sub>3</sub>) and barium titanate (BaTiO<sub>3</sub>). We found the dielectric constant, the breakdown field, and the leakage current to be 150, 5.0 megavolts per centimeter (MV cm<sup>-1</sup>), and 10<sup>-4</sup> amperes per square centimeter at 2 MV cm<sup>-1</sup>, respectively. The results suggest that two-dimensional (2D) carrier density of more than <i>n</i><sub>2D</sub> = 10<sup>14</sup> per square centimeter (cm<sup>-2</sup>) could be modulated by the BHTO gate oxide. We demonstrate an n-type accumulation mode FET and direct suppression of more than <i>n</i><sub>2D</sub> = 10<sup>14</sup> cm<sup>-2</sup> via an n-type depletion-mode FET. We attribute the large dielectric constant, high breakdown field, and low leakage current of BHTO to the nanometer scale stoichiometric modulation of hafnium and titanium.