1-nm-capacitance-equivalent-thickness HfO2/Al2O3/InGaAs metal-oxide-semiconductor structure with low interface trap density and low gate leakage current density

Abstract

We have studied the impact of the Al2O3 inter-layer on interface properties of HfO2/InGaAs metal-oxide-semiconductor (MOS) interfaces. We have found that the insertion of the ultrathin Al2O3 inter-layer (2 cycle: 0.2 nm) can effectively improve the HfO2/InGaAs interface properties. The frequency dispersion and the stretch-out of C-V characteristics are improved, and the interface trap density (D-it) value is significantly decreased by the 2 cycle Al2O3 inter-layer. Finally, we have demonstrated the 1-nm-thick capacitance equivalent thickness in the HfO2/Al2O3/InGaAs MOS capacitors with good interface properties and low gate leakage of 2.4 x 10(-2) A/cm(2). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3698095]