Schottky diode temperature sensor for pressure sensor

Abstract

The small silicon chip of Schottky diode (0.8 × 0.8 × 0.4 mm3) with planar arrangement of electrodes (chip PSD) as temperature sensor, which functions under the operating conditions of pressure sensor, was developed. The forward current-voltage I–V characteristic of chip PSD is determined by potential barrier between Mo and n-Si (ND = 3 × 1015 cm−3). Forward voltage UF = 208 ± 6 mV and temperature coefficient TC = -1.635 ± 0.015 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 μA at 25 °C and IL < 130 μA 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.