Structural and electrical characterization of amorphous lanthanum hafnium oxide thin films

摘要

This paper describes the structural and electronic characterization of lanthanum hafnium oxide thin films deposited by metal organic chemical vapor deposition using a novel precursor mixture. Structural characterization is obtained using x-ray diffraction and cross-sectional transmission electron microscopy and indicates that the as-deposited films and films annealed up to 900℃ remain effectively amorphous. Capacitance voltage and current voltage measurements on metal-oxide-semiconductor capacitors made using the films as a gate dielectric show the films exhibit good electrical integrity following post deposition annealing at temperatures up to 950℃. A dielectric constant, k for the films of 20±1.5 is determined and a density of interface states (at midgap) D_(it) of 3.9 x 10~(11) cm~(-2) eV~(-1) was measured.