Crystallization of Titanium Doped Niobium Dioxide for Neuromorphic Computing Applications

Niobium Dioxide (NbO₂) is a promising material for future-generation computer architectures. NbO₂ undergoes an insulator to metal transition (IMT) that could be used as a switch for certain neuromorphic computing architectures. However, the IMT occurs at high temperature (around 800^°C), and only in fully crystallized material. Doping the NbO₂ with titanium is one promising approach to both reduce the IMT temperature and lower the required annealing temperatures to crystallize NbO₂. In this work, amorphous titanium-doped NbO_x was deposited using physical vapor deposition, and was annealed in a reducing environment at temperatures ranging from 700 – 1000^°C for times ranging from 0 - 60 minutes. After annealing, the samples were analyzed for the amount of crystallization. These crystals were first identified with Raman Spectroscopy, and then an optical microscopy technique was used to determine the percent crystallization across a large area on each sample. It was found that titanium does not change the crystallization temperature of NbO₂, within the range of doping concentrations studied. IMT temperature measurements are ongoing.