A sensor assembly includes a first wafer having a cavity formed therein and a second wafer bonded relative to the first wafer to form a diaphragm over the cavity. A trench is formed in the second wafer in or around the diaphragm and the trench may be filled with an isolating material to help thermally and/or electrically isolate the diaphragm. The diaphragm may support one or more sense elements. The sensor assembly may be used a flow sensor, a pressure sensor, a temperature sensor, and/or any other suitable sensor, as desired.