Schottky-barrier height modulation of metal/In0.53Ga0.47As interfaces by insertion of atomic-layer deposited ultrathin Al2O3

The improvement of the metal/InGaAs interface is essential for the future application of InGaAs metal source/drain Schottky-barrier metal-oxide-semiconductor field-effect-transistors. In this article, on In0.53Ga0.47As, the authors examine the recently proposed method of inserting an ultrathin insulator to modulate the effective Schottky-barrier height (SBH) at the metal/semiconductor interface. Both n-type and p-type In0.53Ga0.47As are investigated by inserting an atomic-layer deposited Al2O3 interlayer. The results indicate that SBH modulation is more effective at the n-InGaAs interface than the p-InGaAs interface for the same Al2O3 thickness. However, the Fermi level at the metal/InGaAs interface is still weakly pinned even after inserting 2 nm Al2O3. The mechanism of the SBH modulation could be attributed to the creation of an electric dipole at the Al2O3/InGaAs interface, which induces a barrier shift. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3610972]