Some common device issues and terminologies

Short Channel Effect: It is the decrease of Vt with the reduction of channel length L

DIBL, Drain Induced Barrier Lowering: As Vds increases, the drain-body depletion region increases and as a result the channel length decreases thus reducing Vt.

Channel Length Modulation: As Vds increases beyond Vd-sat, the saturation point where the surface channel collapses begins to move slightly towards the source, thereby decreasing the effective channel length and decreasing Vt