Nano-laminate vs. direct deposition of high permittivity gadolinium scandate on silicon by high pressure sputtering

Abstract

In this work we use the high pressure sputtering technique to deposit the high permittivity dielectric gadolinium scandate on silicon substrates. This nonconventional deposition technique prevents substrate damage and allows for growth of ternary compounds with controlled composition. Two different approaches were assessed: the first one consists in depositing the material directly from a stoichiometric GdScO_(3) target; in the second one, we anneal a nano-laminate of <0.5 nm thick Gd_(2)O_(3) and Sc_(2)O_(3) films in order to control the composition of the scandate. Metal-insulator-semiconductor capacitors were fabricated with platinum gates for electrical characterization. Accordingly, we grow a Gd-rich Gd_(2-x)Sc_(x)O_(3) film that, in spite of higher leakage currents, presents a better effective relative permittivity of 21 and lower density of defects.