The invention relates to a monolithic
integration type MEMS gas sensor. By integrating a plurality of gas sensors on a substrate, various gases can be detected simultaneously or at different times according to requirements, thereby effectively reducing the production cost and the use cost. The monolithic
integration type MEMS gas sensor comprises a substrate and a
silicon carbide layer on the substrate, an upper surface of the
silicon carbide layer is coated with a
silicon dioxide film, the upper surface of the
silicon oxide film is provided with an insulating layer, the upper surface of the insulating layer is provided with gas sensitive
layers, a heating
electrode is disposed between the gas sensitive
layers and the insulating layer, two or more gas sensitive
layers are disposed, a thermosensitive layer is disposed between the gas sensitive layers and the heating
electrode, the substrate, the
silicon carbide layer, the
silicon dioxide film, the insulating layer, the heating
electrode, the thermosensitive layer and the gas sensitive layers are respectively connected by bonding layers, the upper surface of the gas sensitive layer is coated with a gas sensitive
metal oxide film, andthe gas sensitive
metal oxide film on each gas sensitive layer is made of different or the same material.