This paper investigates the effect of counter doping in an n-Tunneling Field Effect Transistor(nTFET). Effect of various pocket lengths between the source and the channel was investigated. A double gate structure with a 2 nm counter doped pocket provides higher rate of band-to-band tunneling and better on current, thereby increasing the device performance. Steep Subthreshold Swing (SS) of around 23 mV/dec was obtained due to larger band bending at a low operating voltage of 0.5 V. The low leakage current greatly reduces power consumption. The degree of depletion in pocket with smaller dimensions enhances device performance by achieving good electrical characteristics in both above and below threshold regimes. Increase in pocket length degrades the device performance thus affecting the subthreshold swing. (C) 2018 Elsevier B.V. All rights reserved.