Thermal sensing capability and current-voltage-temperature characteristics in Pt/n-GaP/Al/Ti Schottky diodes

We have discussed the thermal sensing capability under a constant current level and current versus voltage (I-V) traces by measuring the temperature of high series resistance Pt/n-GaP/Al/Ti Schottky structures in the 100-320 K range. The R-s values of 35 Omega and 4.50 x 10(3) k Omega for the device have been determined from I-V traces at 320 and 100 K, respectively. The thermal sensing (V-T) curves are expected to give a straight line at each current level. However, the V-T curves have deviated upward from linearity due to the high Rs value of the device after a certain temperature. The deviation point from linearity in V-T traces shifts to higher temperatures with an increase in bias voltage and current level. Thereby, the straight-line interval portion of the V-T curve has become too small with an increase in the current value. The thermal sensing coefficient a changed from 2.49 mV/K at 10 mu A to 3.21 mV/K at 0.50 nA. Therefore, it has been concluded that the Pt/n-GaP/Al/Ti Schottky barrier (SB) is preferable for thermal sensor applications at the small current levels of 0.50, 1.0, 2.0, and 10.0 nA with high sensitivity up to a minimum temperature of 100 K. From I-V curves, q phi(b0) and ideality factor values have ranged from 1.200 eV and 1.066 at 320 K to 0.854 eV and 1.705 at 100 K. It has been reported in the literature that the large SB height leads to a better temperature response.