Amorphous ternary rare-earth gate oxides for future integration in MOSFETs

In this contribution we present results on the structural and electrical properties of amorphous REScO3 (RE = La, Gd, Tb, Sm) and LaLuO3 thin films. The study reveals that these oxides are potential candidates for so-called higher-k dielectrics for forthcoming MOSFET generations. High dielectric constants up to 32, low leakage currents and low interface trap densities are determined for amorphous thin films prepared by pulsed-laser deposition, molecular beam deposition and e-gun evaporation. Moreover, we show that LaLuO3 gate stacks annealed up to 1050 degrees C maintain low leakage current densities without substantial EOT increase. Finally, promising results for n-MOSFETs with GdScO3 as gate dielectric processed on strained silicon-on-insulator substrates are also shown. (C) 2009 Elsevier B.V. All rights reserved