Phase Stabilization of Al:HfO2 Grown on In(x)Gal(1-x)As Substrates (x=0, 0.15, 0.53) via Trimethylaluminum-Based Atomic Layer Deposition

Al:HfO2 is grown on III-V compound substrates by atomic layer deposition after an in situ trimethylaluminum-based preconditioning treatment of the III-V surface. After post-deposition rapid thermal annealing at 700 degrees C, the cubic/tetragonal crystalline phase is stabilized and the chemical composition of the stack is preserved. The observed structural evolution of Al:HfO2 on preconditioned III-V substrates shows that the in-diffusion of semiconductor species from the substrate through the oxide is inhibited. Al-induced stabilization of the Al:HfO2 crystal polymorphs up to 700 degrees C can be used as a permittivity booster methodology with possibly important implications in the stack scaling issues of high-mobility III-V based logic applications.