Control of the interfacial reaction in HfO2 on Si-passivated GaAs

The physical and electrical effects caused by interfacial reactions of HfO2 on Si-passivated GaAs were investigated by various methods. The results showed that the Si layer decreases the diffusion and formation of GaO. Moreover, post-nitridation in HfO2/Si/GaAs significantly reduced the formation of AsO and GaO. The depth profiling data showed that two separated layered structures were formed with HfO2 and a mixture of HfO2 and SiO2 after the annealing process. The crystalline structure and formation of GaO in the film affect the band offsets between GaAs and the high-k HfO2 dielectric. Moreover, the Si passivation effectively suppressed the interfacial defects caused by GaO diffusion during the annealing treatment. The nitridation cause As diffusion to oxygen vacancy of HfO2 result in the increase of the interfacial defect.