Several factors contribute to threshold voltage variability in nanoscale transistors:
Random Dopant Fluctuations: Variations in the number and placement of dopant atoms can significantly affect the threshold voltage. Gate Oxide Thickness Variations: Inconsistencies in the thickness of the gate oxide layer can lead to variations in the electric field and, consequently, the threshold voltage. Channel Length Variations: Deviations in the channel length due to manufacturing imperfections can cause differences in the threshold voltage. Interface Trap Densities: Variability in the density of traps at the semiconductor-oxide interface can impact the threshold voltage. Line Edge Roughness: Variations in the edges of the transistor gate can lead to inconsistencies in the electric field and threshold voltage.
