The Effect of Thermal Annealing and Measurement Temperature on Interface State Density Distribution and Time Constant in Ni/n-GaP Rectifying Contacts

The capacitance–frequency (C–f) and conductance–frequency (G–f) characteristics of the as-deposited and 400°C annealed Ni/n-GaP/Al diode were measured in a temperature range of 100–320 K with steps of 20 K. The values of interface state density Nss and their time constant were obtained from the temperature-dependent C–f and G–f characteristics in the measurement frequency range of 5.0 kHz to 5 MHz. The effect of annealing and measurement temperature on Nss and time constant of a Ni/n-GaP Schottky diode were analyzed from the forward bias voltage to the reverse bias voltage − 0.60 with steps of 0.30 V. The Nss value ranges from 8.8 × 1011 cm−2eV−1 at 0.60 V to 5.71 × 1011 cm−2eV−1 at − 0.60 V for the as-deposited diode, and 1.3 × 1012 cm−2eV−1 at 0.60 V to 5.5 × 1011 cm−2eV−1 at − 0.60 V for the 400°C annealed diode at a measurement temperature of 300 K. The interface state density value increases with high measurement temperature for the as-deposited and annealed diode.