Multi-Layer Structures “Por-Si-on-insulator”/SnOx for Gas Sensing Application

In this paper multi-layer “Por-Si-on-Insulator”/SnOx sensor structures based on porous silicon and non-stoichiometric tin oxide are fabricated and studied. Two-layer structures “macro-porous silicon–meso-porous silicon”, with two types of porous silicon, bound by skeleton elements on a single substrate are grown. Oxide on macro-porous silicon walls and a buried layer of oxidized meso-porous silicon play the role of the insulator. Non-stoichiometric tin oxide deposited onto the extended surface of oxidized macro-porous silicon by magnetron sputtering process is the sensitive layer. The gas sensitivity is studied upon exposure to CO and H2S. The sensitivity of the multi-layer “Por-Si-on-Insulator”/SnOx sensor structures is higher than the sensitivity of tin-oxide film samples.