Ultra-High Sensitivity MEMS Pressure Sensor Utilizing Bipolar Junction
Transistor for -1…+1 kPa
The theoretical model and experimental characteristics of ultra-high
sensitivity MEMS pressure sensor chip for the range of -1…+1 kPa
utilizing a novel electrical circuit are presented. The electrical
circuit uses piezosensitive differential amplifier with negative
feedback loop (PDA-NFL) based on two bipolar-junction transistors (BJT).
The BJT has a vertical structure of n-p-n type (V-NPN) formed on a
non-deformable chip area. The circuit contains eight piezoresistors
located on a profiled membrane in the areas of maximum mechanical
stresses. The circuit design provides a balance between high pressure
sensitivity (S = 44.9 mV/V/kPa) and fairly low temperature dependence of
zero output signal (TCZ = 0.094% FS/°C). Additionally, high membrane
burst pressure of P = 550 kPa was reached.