Physical and electrical characterizations of ultrathin Si-rich Hf-silicate film and Hf-silicate/SiO2 bilayer deposited by atomic layer chemical vapor deposition

Abstract

Hf-silicate films and Hf-silicate/SiO2 bilayers were fabricated on Si(100) to study SiO2 buffer layer effects. Hf-silicate layers were grown by atomic layer chemical vapor deposition using alternate supply of tetrakis-diethylamido-hafnium (Hf[N(C2H5)2]4) and tetra-n-butyl-orthosilicate [Si(OnBu)4] precursors. Ultrathin SiO2 buffer layers effectively suppressed Hf-rich phases and dislocations found at Hf-silicate/Si interfaces in Hf-silicate samples. These effects resulted in the significantly improved electrical properties of bilayers, compared to Hf-silicate films, such as low leakage current density (Jg), low flatband voltage (Vfb) shift, and high breakdown voltage (VBD).