High-Sensitivity MEMS Pressure Sensor Utilizing Bipolar Junction Transistor with Temperature Compensation

The paper presents MEMS pressure sensor chip utilizing novel electrical circuit with bipolar-junction transistor-based (BJT) differential amplifier with negative feedback loop (PDA-NFL). Pressure sensor chips with two circuits have been manufactured and tested: the first chip uses circuit with vertical n-p-n (V-NPN) BJTs and the second – circuit with horizontal p-n-p (L-PNP) BJTs. The demonstrated approach allows for increase of pressure sensitivity while keeping the same chip size. It also can be used for chip size reduction and increase of pressure overload capability while maintaining the same pressure sensitivity. Significant reduction of both noise and temperature instability of output signal has been demonstrated using transistor amplifier with negative feedback loop.