Two-step Fabrication of Large Area SiO2/Si Membranes

Abstract

Two-step fabrication technique of SiO2/Si membrane combining the deep local etching of double side polished and thermally oxidized silicon <100> wafer in tetramethylammonium hydroxide (TMAH) water solution and SF6/O2 reactive ion etching is presented in this study. The influence of temperature on stress and deformations of membrane was simulated using Solid Works software. The study of influence of photomask opening size on etching rate shows that TMAH etching rate V = 0.44 mm/min is higher for the biggest opening, whereas for smaller openings the etching rate is evidently decreased. It was revealed that TMAH during long etching time smoothly affects thermally grown silicon dioxide film as surface roughness Ra increases from 0.558 μm to 0.604 μm. SF6/O2 reactive etching rate is smoothly dependent on deep opening size when plasma power density varies from 0.25 W/cm2 to 1.0 W/cm2.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3090

Keywords

• SiO2/Si membrane
• TMAH etching
• reactive ion etching
• surface roughness