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arXiv2021

Pressure Sensor with New Electrical Circuit Utilizing Bipolar Junction Transistor

High sensitivity MEMS pressure sensor chip for different ranges (1 to 60 kPa) utilizing the novel electrical circuit of piezosensitive differential amplifier with negative feedback loop (PDA-NFL) is developed. Pressure sensor chip PDA-NFL utilizes two bipolar-junction transistors (BJT) with vertical n-p-n type structure (V-NPN) and eight piezoresistors (p-type). Both theoretical model of sensor response to pressure and temperature and experimental data are presented. Data confirms the applicability of theoretical model. Introduction of the amplifier allows for decreasing chip size while keeping the same sensitivity as a chip with classic Wheatstone bridge circuit.

physics.app-ph↗

arXiv2021

Schottky diode temperature sensor for pressure sensor

The small silicon chip of Schottky diode (0.8x0.8x0.4 mm3) with planar arrangement of electrodes (chip PSD) as temperature sensor, which functions under the operating conditions of pressure sensor, was developed. The forward I-V characteristic of chip PSD is determined by potential barrier between Mo and n-Si (ND = 3x1015 cm-3). Forward voltage UF = 208 mV and temperature coefficient TC = -1.635 mV/C (with linearity kT <0.4% for temperature range of -65 to +85 C) at supply current IF = 1 mA is achieved. The reverse I-V characteristic has high breakdown voltage UBR > 85 V and low leakage current IL < 5 {\mu}A at 25 C and IL < 130 {\mu}A at 85 C (UR = 20 V) because chip PSD contains the structure of two p-type guard rings along the anode perimeter. The application of PSD chip for wider temperature range from -65 to +115 C is proved. The separate chip PSD of temperature sensor located at a distance of less than 1.5 mm from the pressure sensor chip. The PSD chip transmits input data for temperature compensation of pressure sensor errors by ASIC and for direct temperature measurement.

physics.app-ph↗