Pulsed laser deposition of aluminate YAlO₃ and LaAlO₃ thin films for alternative gate dielectric applications

Amorphous aluminate YAlO3 (YAO) thin films on n-type silicon wafers as gate dielectric layers of metal-oxide-semiconductor devices are prepared by pulsed laser deposition. As a comparison, amorphous aluminate LaAlO3 (LAO) thin films are also prepared. The structural and electrical characterization shows that the as-prepared YAO films remain amorphous until 900 °C and the dielectric constant is ∼ 14. The measured leakage current of less than 10-3A/cm2 at a bias of VG=1.0 V for ∼ 40-nm-thick YAO and LAO films obeys the Fowler-Nordheim tunneling mechanism. It is revealed that the electrical property can be significantly affected by the oxygen pressure during deposition and post rapid thermal annealing, which may change the fixed negative charge density at the gate interface.