Interfacial and electrical properties of HfO ₂ gate dielectrics grown on GaAs by atomic layer deposition using different oxidants

In this paper, we examined the effects of two different oxidants (H ₂O and O ₃) used during the atomic layer deposition (ALD) of HfO ₂ films on GaAs, particularly focusing on its interfacial and electrical properties. In comparison with the H ₂O-based ALD process, the O ₃-based process produced a large amount of elemental As and Ga-O related bonds near the HfO ₂/GaAs interface due to its stronger oxidizing power. High interface state and border trap densities of the O ₃-based sample degraded the low-field electrical stability, which was confirmed by the capacitance and leakage current measurements under various voltage-stressing conditions. However, in terms of high-field stability, the O ₃-based sample showed a much stronger resistance to stress-induced trap generation than the H ₂O-based sample.