Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Actually, threshold voltage may be affected by narrow-width and narrow-length effects.
For short channels, the threshold voltage is reduced due to reduced gate control because of the proximity of the S/D regions to the channel.
For narrow channels, threshold voltage increases due to the fact that the fringing fields from the gate raises the surface potential at the edges of the channel.
Hope it helps.