Interface and Electrical Properties of Atomic-Layer-Deposited HfAlO Gate Dielectric for N-Channel GaAs MOSFETs

摘要

The interface and electrical properties of HfAlO dielectric formed by atomic layer deposition(ALD) on sulfur-passivated GaAs were investigated. X-ray photoelectron spectroscopy (XPS)revealed the absence of arsenic oxides at the HfAlO/GaAs interface after dielectric growth and post-deposition annealing at 500 °C. A minimal increase in the amount of gallium oxides at the interfacewas detected between the as-deposited and annealed conditions highlighting the effectiveness ofHfAlO in suppressing gallium oxide formation. An equivalent oxide thickness (EOT) of ～ 2 nm hasbeen achieved with a gate leakage current density of less than 10~(-4) A/cm~2. These results testify agood dielectric interface with minimal interfacial oxides and open up potential for further investigationof HfAlO/GaAs gate stack properties to determine its viability for n-channel MOSFETs.