Sintering behavior and densification mechanism of MoOx targets obtained by hot pressing

MoOx targets for magnetron sputtering Mo-O films were obtained by vacuum hot pressing sintering. MoOx powder was obtained by hydrogen reduction of MoO3, and the O/Mo atomic ratio was determined by the k-value method. The sintering behavior and densification mechanism of the MoOx target were analyzed by exploring the influence of hot pressing sintering pressure, temperature, and holding time on the target's density, phase composition, and morphology. MoOx targets with different oxygen content were sintered using MoOx powder with O/Mo of 2.838, 2.679, and 2.494, respectively. The results reveal that complex reactions occur in the shrinkage stage of sintering. The content of Mo4O11 increases, the content of Mo9O26 and MoO2 decreases, and the oxygen content of the targets is positively correlated with the content of MoO2 in MoOx powder. Subsequently, Mo4O11 grain growth densifies the targets. Excessive sintering temperature and pressure will cause the decomposition of Mo4O11, resulting in a decrease in density. Finally, the MoO2.623 target with a density of 97.85 % was obtained by hot pressing sintering with MoO2.494 as raw material at 973 K, 40 MPa, and holding temperature for 60 min. Raman mapping shows the MoO2.623 target with 16.9 wt% MoO2 and 83.1 wt% Mo4O11, and the phase distribution was uniform.