Nanometer-scale patterning on titanium thin film with local oxidation of scanning probe microscope

Nanometer-scale oxidized patterns were fabricated on titanium (Ti) films deposited on silicon wafer using an atomic force microscope (AFM) based field-induced oxidation process. Titanium surfaces can be oxidized at room temperature under ambient conditions with the tip of an atomic force microscope when applying a negative bias voltage between surface and tip. We determined that the size of the oxide patterns was dependent on tip-bias voltages, scanning speed, and relative humidity. We found that the attainable oxide features of titanium patterns were improved by increasing the scanning speed, tip-bias voltage and also by lowering the relative humidity. Fabrication of nanometer-scale structures on the Ti-metal film by AFM-based field-induced oxidation and subsequent chemical wet etching of the titanium in a dilute hydrofluoric acid (HF) was demonstrated. Patterns of Ti lines below 100 nm in width were successfully fabricated by the above-described method.