Edge-defined patterning of hyperfine refractory metal silicide MOS structures

Edge-defined patterning was used to obtain hyperfine (< ¼ µm) refractory metal silicide MOS structures. A patterning technique, using standard optical lithography and advanced etching technology, was developed and proven to result in submicrometer structures of controllable dimensions. Hyperfine MoSi2/SiO2/Si MOS structures were realized using a vertical aluminum step defined by CCl4plasma etching. The MoSi2patterning was performed using anisotropic planar etching in NF3. Functional relationships between Al step height (0.3- 0.9 µm), MoSi2film thickness (0.3-1.0 µm), and the resulting silicide linewidth (0.1-0.25 µm) and line height (0.3-0.9 µm) were investigated. It was found that the linewidth and height could be independently controlled.