Temperature dependence of the electrical characteristics in Au-n-type InP Schottky diodes

The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au-n-type InP Schottky diodes are measured over the temperature range 120–300 K. It is found that apparent barrier heights qφB obtained from I-V curves increase linearly with increasing temperature. The intercept voltage V0 of the 1/C2 vs V curve is observed to decrease with increasing temperature. The quantity q(V0+Vn+kT/q) shows a linear temperature variation, where qVn denotes the semiconductor Fermi level. Theoretical analysis is also developed, including the effects of an interfacial layer between the metal and semiconductor. Increase in qφB with temperature is due to the presence of the electron tunneling barrier in the interfacial layer. It is shown that the temperature variation of the barrier height qφB0 is closely related to that of q(V0+Vn+kT/q): for a sufficiently thin interfacial layer, we have dqφB0/dT ≊dq(V0+Vn +kT/q)/dT<0. As the interfacial layer is thick, ‖dqφB0/dT‖ becomes small, and we have dq(V0+Vn+kT/q) /dT<dqφB0/dT<0.