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

Abstract
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 Al 2 O 3 dielectrics on GaAs grown by ALD. The leakage current in ultrathin Al 2 O 3 on GaAs is comparable to or even lower than that of state-of-the-art Si O 2 on Si, not counting the high- k dielectric properties for Al 2 O 3 . A Fowler-Nordheim tunneling analysis on the Ga As ∕ Al 2 O 3 barrier height is also presented. The breakdownelectric field of Al 2 O 3 is measured as high as 10 MV ∕ cm as a bulk property. A significant enhancement on breakdownelectric field up to 30 MV ∕ cm is observed as the film thickness approaches to 1 nm .