Electrical properties of Ta/n-Si and Ta/p-Si Schottky barrier diodes obtained by sputtering of tantalum (Ta) metal on semiconductors have been investigated. The characteristic parameters of these contacts like barrier height, ideality factor and series resistance have been calculated using current voltage (I-V) measurements. It has seen that the diodes have ideality factors more than unity and the sum of their barrier heights is 1.21 eV which is higher than the band gap of the silicon (1.12 eV). The results have been attributed the effects of inhomogeneities at the interface of the devices and native oxide layer. In addition, the barrier height values determined using capacitance-voltage (C-V) measurements have been compared the ones obtained from I-V measurements. It has seen that the interface states have strong effects on electrical properties of the diodes such as C-V and Rs-V measurements. © 2010 Elsevier Ltd. All rights reserved.