Enhancement in interface robustness regarding thermal oxidation in nanostructured Al2O3 deposited on 4H-SiC

Abstract

Experimental evidences of enhanced stability of Al2O3 /SiC structures following thermal annealing are presented. 5- and 40-nm-thick Al2O3 films evaporated on the Si- and C-terminated faces of 4H-SiC were annealed up to 1000 °C in different atmospheres, leading to crystallization and densification of Al2O3, with an increase in the band gap. Exposure to O2 at high temperatures produced SiO2 and AlSixOy at the Al2O3 /SiC interface, with less silicate on the Si-terminated face. Annealing in N2 before exposure to O2 hindered oxygen diffusion and exchange, leading to more stable thin film structures from the point of view of atomic transport.