Techniques for reducing the reverse short channel effect in sub-0.5 μm CMOS

Experimental evidence is presented demonstrating that the reverse short channel effect (RSCE) is initiated by damage from the source-drain implants which, in turn, causes defect-enhanced diffusion of the channel dopants toward the gate oxide interface. Several process options that attempt to modify the diffusion of the channel implants, such as channel doping profile engineering, vacancy injection into the silicon substrate through sputter-etch damage, and TEOS depositions on silicon followed by rapid thermal annealing, are described which reduce the magnitude of the reverse short channel effect. This often results in an increase in device short channel margin of as much as 50 nm and a concomitant increase in the n-channel drive current of as much as 10%.<>