Electrical properties of Au–Cu/ZnO/p-Si diode fabricated by atomic layer deposition

Abstract

The electrical properties of the Au–Cu/ZnO/p-Si diode were investigated with the temperature dependent current–voltage measurements in a wide temperature range from 220 to 360 K with 20 K steps and also frequency dependent capacitance–voltage and conductance–voltage measurements using admittance spectroscopy by changing frequency from 1 to 1000 kHz. The ZnO thin film layer was deposited by atomic layer deposition technique (ALD) to obtain homogenous interface layer and this layer surface was characterized with AFM analyses. Assuming thermionic emission (TE) model, diode parameters such as barrier height and ideality factor were determined for the Au–Cu/ZnO/p-Si diodes and the strong temperature dependence of these values were modeled by TE model with modified by Gaussian distribution of the barrier height. Therefore, the observed non-ideal current behavior was discussed on the basis of barrier inhomogeneity and the presence of native oxide interfacial layer in the diode. The mean barrier height was found as 1.38 eV with 0.18 standard deviation, and the Richardson constant modified by this model was obtained as 28 A/cm2k2 close to the theoretical value. Additionally, the distribution profile of the interface states and series resistance value were evaluated by the capacitance and conductance characteristics. It could be seen from the results that both of them strongly depends on the device frequency. As a result of these works, fabricated Au–Cu/ZnO/p-Si diodes may be used for next technological application in wide range temperature in industry.