Characterization of Al2O3/LaAlO3/SiO2 Gate Stack on 4H-SiC After Post-Deposition Annealing

We fabricated Al
₂
O
₃
/LaAlO
₃
/SiO
₂
(ALS) gate stacks on 4H-SiC, with LaAlO
₃
(LAO) film being annealed in O
₂
atmosphere. The ALS gate stack annealed at 700 °C exhibits a much higher breakdown effective electric field (
${E}_{\text {eff}}$
), which is approximately 1.8 times higher than that of traditional SiO
₂
gate oxide. The ALS gate stack also yields a low interface state density (
${D}_{\text {it}}$
) thanks to the intact LAO film. However, an annealing temperature as high as 800 °C induced traps in the LAO film and deteriorated the SiO
₂
–SiC interface. The 700 °C-annealed LAO film with a high dielectric constant (
$\kappa $
) of 14 and a low trap density, coupled with good electrical characteristics, makes it a promising gate dielectric for SiC power metal-oxide-semiconductor (MOS) device applications.