A novel submicron-gap electrode fabrication technology using thermal oxidation

A novel and reproducible method to fabricate submicron-gap electrodes using thermal oxidation has been presented. In this method, oxidation process determines the gap distance. The micron-level silicon electrode gaps with different shapes were first generated on the silicon wafer by conventional photolithography followed by deep reactive ion etching process. Then thermal oxidation was conducted to realize the transition from silicon to silicon dioxide, i.e. reduce the gap width. Finally, the planar electrodes with sub-micron spacing were formed by metallization and photolithography. Scanning electron microscopy (SEM) was used to examine the electrode configuration and the electrical properties of as-prepared electrode pairs were also characterized. The results showed that using the method investigated in this work, Au electrodes with a submicron-sized gap could be easily fabricated, with good uniformity and reproducibility.