Scaling has played an important role in reducing the size of the transistor so as to govern the Moore's law, but due to down scaling of the transistor size there is deterioration in the performance of the transistor. In this book we have discussed such effects and tried to minimise these effects. We have discussed about the recent available technology i.e different gated structures such as single gate, double gate, triple gate and gate all around which will control the electrostatic potential in the channel and reduces these short channel effects. Also we have varied different physical parameters so as to reduce these quantum effects.