Single Silicon Wafer Micromachined Thermal Conduction Sensor

摘要

A single silicon wafer micromachined thermal conduction sensor is described. The sensor consists of a heat transfer cavity with a flat bottom and an arbitrary plane shape, which is created in a silicon substrate. A heated resistor with a temperature dependence resistance is deposed on a thin film bridge, which is the top of the cavity. A heat sink is the flat bottom of the cavity and parallel to the bridge completely. The heat transfer from the heated resistor to the heat sink is modulated by the change of the thermal conductivity of the gas or gas mixture filled in the cavity. This change can be measured to determine the composition concentration of the gas mixture or the pressure of the air in a vacuum system.

主权项

1. A single silicon wafer micromachined thermal conduction sensor consists of a heat transfer cavity having a flat bottom and an arbitrary plane shape, which is created in a silicon substrate, a frame resulted by creating the cavity in the substrate and having a curved side wall supporting and surrounding the cavity, a thin film bridge suspending over the cavity and extending to the edge of the frame, which has a wide central section and at least two side narrow sections on the two opposite sides of the central section, a heated resistor disposed at the surface of the central section of the bridge, which has a temperature dependence resistance, a heat sink being the flat bottom of the cavity and parallel to the bridge, a temperature sensor disposed on the surface of the frame.