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

© 2015 Elsevier B.V. The authors acknowledge “CAI de Técnicas Físicas” and “CAI de Espectroscopía” of the “Universidad Complutense de Madrid” for sample fabrication and FTIR measurements respectively. The microscopy works have been conducted in the "Laboratorio de Microscopias Avanzadas" at "Instituto de Nanociencia de Aragón” of the “Universidad de Zaragoza”. Authors thank them their technical support and expertise. This work was funded by the project TEC2010-18051 from the Spanish “Ministerio de Economía y Competitividad”, and the “Formación de Personal Investigador” program under grant BES-2011-043798.
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.
Ministerio de Economía y Competitividad (MINECO)
Spanish “Formación de Personal Investigador”
Depto. de Estructura de la Materia, Física Térmica y Electrónica
Fac. de Ciencias Físicas
TRUE
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