We present a silicon carbide (SiC) based surface micromachined nanoreactor for in-situ characterization of reactions between solid nanostructured materials and gasses in transmission electron microscopes (TEMs). For the first time SiC is used as construction material for this device and a novel design of gas-microchannel with a two-level height is implemented. The use of SiC compared to the standard construction materials allows for easier and more reliable fabrication of the complete microsystem and for improved performance in terms of temperature. Additionally, the two-level height channel eases the loading of the specimens without affecting the sensitivity in the gas analysis.