A Low-Cost Short-Distance Thermal Conduction Pressure Sensor

A low-cost thermal pressure sensor based on short-distance thermal conduction and used in atmospheric pressure range has been explored. This simple device consists of a heater made of a polysilicon resistor, a heat sink made by the silicon substrate and a tiny air gap between them. With innovative ideas and simple processes, the gap can be made in the order of nanometers inexpensively, which significantly increases the measurement range of the sensor. Devices capable of measuring 700kPa (7atm) or more have been fabricated with a 3-mask, 3pm and CMOS compatible process. The device can be made as small as 50x50pm2, less than the size of a standard bonding pad. The simple process and low cost associated with these devices could make commercial adaptation promising.