High-k gadolinium scandate on Si obtained by high pressure sputtering from metal targets and in-situ plasma oxidation

Abstract

This article studies the physical and electrical behavior of Gd2-xScxO3 layers grown by high pressure sputtering from metallic Gd and Sc targets. The aim is to obtain a high permittivity dielectric for microelectronic applications. The films were obtained by the deposition of a metallic nanolaminate of Gd and Sc alternating layers, which is afterwards in-situ oxidized by plasma. The oxide films obtained were close to stoichiometry, amorphous and with minimal interfacial regrowth. By fabricating metal-insulator-semiconductor capacitors we found that a moderate temperature annealing is needed to enhance permittivity, which reaches a high value of 32 while keeping moderate leakage. Finally, the feasibility of interface scavenging in this material with Ti gate electrodes is also demonstrated.