| 摘要 |
A process for forming different types of sensors, including metal oxide (10), calorimetric (44), and heterojunction (48), on the same semiconductor chip includes the steps of doping a top surface of a silicon substrate (16) with boron to form a diffusion region (18) for a resistive heater, forming a first silicon nitride layer (24) on the diffusion region, forming a first metal layer (26) on the first silicon nitride layer to provide a resistive temperature detector, forming a second silicon nitride layer (28) on the first metal layer, forming a second metal layer (34) on the second silicon nitride layer, and etching a sensing cavity (40) underneath and adjacent to the diffusion region using an anisotropic wet etchant and the diffusion region as an etch-stop. A metal oxide layer (36) is formed over the second metal layer for a metal oxide or heterojunction sensor. The sensor can optionally be suspended by tethers (38) within the sensing cavity.
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