We report the realization of a miniaturized H 2S gas sensor using micromachining of silicon substrate assisted by a porous oxide formation for selective patterning of CuO-doped SnO 2 layers. The formation of sensing material (SnO 2/CuO) is through a sol-gel spin coating process. The sol-gel adhesion to porous silicon dioxide is significantly better than regular plain SiO 2 surfaces. The formation of a nano-porous and highly textured oxide layer is feasible through a sequential reactive ion etching process which utilizes one short step of reactive etching followed by another step of passivation. By repeating these subsequences for many times, desired textures are created which in turn would lead to a highly selective deposition of the sol-gel layer on the porous silicon dioxide. The sensor response to various H 2S concentrations has been investigated showing a high sensitivity. Since the device is realized on a silicon-based membrane, the effect of electric current passing through the heating element has also been studied. SEM and XRD analyses have been used to investigate the surface morphology and crystallinity of SnO 2 and porous SiO 2 films.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry
- Electrical and Electronic Engineering