New study of the abnormal behavior of the low temperature dependence of the current in inhomogeneous Schottky diode

Abstract

In this study, we show clearly why unexpected observations have been reported in the current-voltage curves of Schottky diodes, containing barrier inhomogeneities generated by using the analytical results based on a Gaussian distribution model of barrier heights. The Chand's calculations have shown that the current (saturation current) at low temperatures may exceed the current (saturation current) at high temperatures when the effective barrier height is calculated from an appropriate integral with integration limits À∞ and +∞. In this new study, we show that the method followed by Chand to remove these anomalies is not accurate enough. We prove that the origin of these anomalies stems from the nature of a proper function f(ϕ) that moves to the negative barrier heights and takes large value of the integral at low temperatures than at high temperatures when it has large standard deviation (σ) and the discrepancies are not due to the integration limits as Chand concluded. In order to obtain results consistent with the thermionic emission-diffusion theory, the standard deviation must have lower values.

Temperature dependence of the inhomogeneous parameters of the Mo/4H–SiC Schottky barrier diodes

“…and the temperature coefficient a f for Mo/4H-SiC diodes at various doses and different diameters. current at low temperatures when compared to the saturation current at high temperatures [22]. The BEEM studies have reported the low values of the standard deviation; 0.03, 0.04 [25], 0.02 [26], and 0.013-0.022 V [27] at room temperature and ∼0.011-0.021 V [24] in the temperature range of 129-252 K.…”

“…It presents the Werner's model for inhomogeneous Schottky diode. Most of the workers use this equation for extracting the inhomogeneous parameters f and s. However, when we apply this method the Schottky diodes exhibit higher currents at low temperatures than at high temperatures [15,22]. This observation is thus inconsistent with the thermionic emission-diffusion theory.…”

Intersection of 4H-SiC Schottky diodes I–V curves due to temperature dependent series resistance

“…Chand and Bala [4] studied inhomogeneous diodes and observed the crossing of the I-V curves measured at low temperatures up to 100 K with I-V curves measured at higher temperatures. Latreche and Ouennoughi [5] carried out recently a similar study in which this effect has been confirmed, but the physical interpretation of the effect was rather different. Osvald and Horváth [6] simulated by the drift-diffusion approximation I-V curves of n-Si Schottky diodes with a p-type surface inversion layer in the temperature region 80-320 K. The intersection of the I-V curves appeared already in the linear section of the semi-logarithmic I-V curves.…”