REACTIVE ION ETCHING OF SILICON TRENCHES USING SF6/O-2 GAS-MIXTURES

Anisotropic etching of deep trenches in single-crystal Si has been obtained using reactive ion etching with SF6/O2 gas mixtures for the first time. The influence of wafer temperature, total gas pressure, and O2 content on profile control and etch selectivity (Si:SiO2) has been determined. A high anisotropy and selectivity (18:1) have been achieved at 25% O2 content. Scanning electron microscopy and Auger electron spectroscopy techniques have been used to study the trench profile and surface roughness. Methods for post-reactive ion etching surface treatment have been explored to remove surface roughness.