Properties of Al2O3 thin films deposited on 4H-SiC by reactive ion sputtering

TL;DR

This study investigates the electrical, morphological, and chemical properties of Al2O3 thin films on 4H-SiC deposited via reactive ion sputtering, highlighting improvements after rapid thermal annealing.

Contribution

It provides new insights into the effects of rapid thermal annealing on Al2O3/4H-SiC interfaces and their electrical characteristics.

Findings

RTA reduces electron trapping in Al2O3 films.

Permittivity of Al2O3 films increases up to 6ε0 after RTA.

Fowler-Nordheim barrier height is 2.37 eV, between SiO2/4H-SiC and Al2O3/4H-SiC systems.

Abstract

In this work, the electrical properties of Al2O3 films deposited by reactive ion sputtering were investigated by means of morphological, chemical and electrical characterizations. This insulating layer suffers of an electron trapping that is mitigated after the rapid thermal annealing (RTA). The RTA improved also the permittivity (up to 6{\epsilon}0), although the negative fixed charge remains in the order of 1012cm-2. However, the temperature dependent electrical investigation of the MOS capacitors demonstrates that the room temperature Fowler-Nordheim electron barrier height of 2.37 eV lies between the values expected for SiO2/4H-SiC and Al2O3/4H-SiC systems.