Temperature-dependent current-conduction mechanisms in Au-InP Schottky barrier diodes (SBDs)

摘要

In this study, we have investigated the forward bias current-voltage (I-V) characteristics of Au-InP Schottky barrier diodes (SBDs) in the temperature range of 160-400 K. Experimental results show that the values of ideality factor (n), zero-bias barrier height Φ _(Bo)(I-V) were found strongly temperature dependent and while the Φ _(Bo)(I-V) increases, the n decreases with increasing temperature. Such behavior of Φ _(Bo)(I-V) and n is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution (GS) of barrier heights (BHs) at Au-InP interface. We attempted to draw a Φ _(Bo) vs q/2kT plot to obtain evidence of a GS of the BHs, and the values of ?Φ _(Bo)=0.89eV and so= 0.137 V for the mean barrier height and standard deviation at zero bias, respectively, have been obtained from this plot. Thus, a modified ln(I _o/T ~2)-q ~2Φ _(Bo) ~2/2(kT) ~2 vs q/kT plot gives Φ _(Bo) and Richardson constant A* as 0.904 eV and 10.35 A/cm ~2K ~2, respectively, without using the temperature coefficient of the barrier height. This value of the Richardson constant 10.35 A/cm ~2K ~2 is very close to the theoretical value of 9.8 A/cm ~2K ~2 for n-InP. Hence, it has been concluded that the temperature dependence of the forward I-V characteristics of the Au-InP SBDs can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the BHs.