Voltage-temperature characteristics of W/n-GaAs Schottky diodes activated by the constant forward current: application as temperature sensors

The W/n-GaAs Schottky diodes A and B were fabricated by rf sputter deposition of W at rf powers of 400 and 300 Watt, respectively. The Schottky diode B was subjected to a 90 min. anneal at 390°C in Ar ambient. The forward voltage-temperature (V_F-T) measurements were carried out in the temperature range 140-363 K at constant activation currents (I_F) in the range 2.5-500 μA. The V _F-T characteristics were linear for I_F ⩾50 μA in the diode A and for I_F⩾2.5 μA in the diode B. From the V_F-T characteristics at 100 μA, the values of -2.31 mVK^-1 and 2.59 mVK^-1 for the temperature coefficient of the forward bias voltage (dV_F/dT) for the diodes A and B, respectively, were determined. The value of dV_F /dT for the diode B was quite close to the theoretical value of -2.70 mVK^-1. For constant currents in the range 2.5 μA<I_F<100 μA, the linear extrapolations of the experimental V_F-T characteristics in the diode B intersected the V_F axis at the same point which provided the values of 0.86 V and 0.70 V for the barrier height at 0 K and 300 K, respectively, independent of the value of the activation current. The barrier height values thus obtained are in good agreement with the value obtained by other method