Effect of strained-Si thickness on electrical properties of furnace grown gate oxide has been investigated. Interface state density (D-it) versus energy characteristics shows that Dit increases with decreasing strained-Si thickness, probably due to the presence of Ge at the interface. From conductance measurement, two different types of traps are observed in the gate oxide. In thinner strained-Si samples, the onset of F-N tunneling happens at higher voltages, indicating thicker gate oxide. Gate voltage oscillations were observed during constant current stress under gate injection at low stress current. This sinusoidal characteristics are possibly due to the trapping and detrapping of charges in the oxide. (C) 2004 Elsevier B.V. All rights reserved.