Leakage current and breakdown electric-field studies on ultrathin atomic-layer-deposited Al₂O₃ on GaAs

Atomic-layer deposition (ALD) provides a unique opportunity to integrate high-quality gate dielectrics on III-V compound semiconductors. We report detailed leakage current and breakdown electric-field characteristics of ultrathin Al₂O₃ dielectrics on GaAs grown by ALD. The leakage current in ultrathin Al₂O₃ on GaAs is comparable to or even lower than that of state-of-the-art SiO₂ on Si, not counting the high-k dielectric properties for Al₂O₃. A Fowler-Nordheim tunneling analysis on the GaAs/Al₂O₃ barrier height is also presented. The breakdown electric field of Al₂O₃ is measured as high as 10 MV/cm as a bulk property. A significant enhancement on breakdown electric field up to 30 MV/cm is observed as the film thickness approaches to 1 nm.