In 0.53 Ga 0.47 As n-metal-oxide-semiconductor field effect transistors with atomic layer deposited Al2O3, HfO2, and LaAlO3 gate dielectrics

Abstract

The authors have fabricated In0.53Ga0.47As metal-oxide-semiconductor transistors and studied the effects of different atomic layer deposited (ALD) gate dielectrics (Al2O3, HfO2, and LaAlO3) on device performance including the equivalent oxide thickness (EOT) scalability, the current driving capability, and the interface quality. ALD Al2O3 shows the best interface quality with InGaAs substrates, but it can only obtain EOT of about 2.4 nm due to its comparably low dielectric constant (κ=8.1). LaAlO3 has higher dielectric constant (κ=12.1) than Al2O3 and achieves subthreshold swing of 84 mV/decade for 1.3 nm EOT. HfO2 (κ=17.0) demonstrates the minimum EOT of 1 nm with high drive current of 133.3 mA/mm (L=5 μm).