Enhanced electrical properties by post thermal nitridation in atomic-layer-deposited HfO$_{2}$ on InP

We investigated the effects of post-nitridation in HfO$_{2}$ thin films grown on InP by atomic layer deposition on the structural, chemical, and electrical properties of the resultant film as well as its thermal stability compared to samples that were only thermally-annealed by comprehensive physical, electrical, and theoretical analyses. By post-deposition annealing under NH$_{3}$ vapor at 600${^\circ}$, an InN layer formed at the HfO$_{2}$/InP interface and ionized NH$_{x}$ was incorporated in the HfO$_{2}$ film. Accordingly, interfacial reactions were effectively suppressed in nitrided HfO$_{2}$/InP by controlling out-diffusion of In or P atoms from the substrate. Nitridation of HfO$_{2}$/InP modulated energy band parameters at the HfO$_{2}$/InP interface, thereby decreasing leakage current. Moreover, the nitridation process significantly suppressed the generation of D$_{it}$ due to controlled diffusion of In and P. DFT calculations showed that In$_{i}$ and P$_{i}$ in HfO$_{2}$ are closely related, with defect states within the band gap of InP.