Simulation Study of Implantation Angle Variation and Its Impact on Device Performance

A simulation platform was established to evaluate device performance affected by ion implantation angle variation. Modeling of a one-dimensional wafer scanning system was performed to estimate the angle variation. Process simulation for fin field effect transistors (FinFET) revealed that twist angle affects dopant dose retention in the fin structure. However, the fin structure twists as the arm holding the wafer rotates during scanning. This causes twist angle variation which depends on the length of the rotation arm and the tilt angle. Maximum variation in twist angle occurs near the bottom edge of the wafer. Such variation may increase device driving and leakage current when more twist angle results in more dopant retention in the source/drain extension regions.