Channel edge doping (CED) method for reducing the short-channel effect

A new fabrication process for short-channel MOSFET's, the channel edge doping method (CED), is proposed. In this method, highly doped regions are self-aligned with the channel edges by using a silicon dioxide liftoff technique. The spread of source/drain depletion-regions toward the channel is suppressed by the highly doped regions. Thus the short-channel effect can be prevented. Using the CED method, n-channel MOSFET's with effective channel length down to 0.9 µm are fabricated. Their characteristics are compared with those for conventionally processed MOSFET's and the effect of the CED method for reducing the short-channel effect is confirmed.