A thick silicon dioxide fabrication process based on electrochemical trenching of silicon

Abstract

Thick silicon dioxide films have recently been proposed for sensor applications (thermal isolation in high-temperature sensors, gas sensors, etc.). In this paper a simple and low cost method to produce thick silicon dioxide layers (thickness of several tens of microns) is reported. The process is based on the photoelectrochemical etching of silicon in HF solution. This technique is here used to produce deep high aspect ratio regular trenches, which are then completely oxidized to obtain a thick silicon dioxide layer.