By combining an anneal process for adjusting the effective channel length and a substantially diffusion-free anneal process performed after a deep drain and source implantation, the vertical extension of the drain and source region may be increased substantially without affecting the previously adjusted channel length. In this manner, in SOI devices, the drain and source regions may extend down to the buried insulating layer, thereby reducing the parasitic capacitance, while the degree of dopant activation and thus series resistance in the extension regions may be improved. Furthermore, less critical process parameters during the anneal process for adjusting the channel length may provide the potential for reducing the lateral dimensions of the transistor devices.