Improved Performance of Multilayer TiON/TaON Structure as Gate Dielectric for InGaAs Metal-Oxide-Semiconductor Capacitor

The interfacial and electrical properties of the multilayer TiON/TaON/InGaAs and TaON/TiON/InGaAs metal-oxide-semiconductor (MOS) capacitors fabricated by alternately RF-sputtering method are investigated and compared. Experimental results show that the former exhibits lower interface-state density, smaller gate leakage current, larger equivalent dielectric constant and higher device reliability than the latter. This is attributed to the fact that the ultrathin TaON interlayer formed on sulfur-passivated InGaAs can effectively reduce the density of defective states and unpin the Femi level at the TaON/InGaAs interface, thus greatly improving the interfacial and electrical properties of the device.