A constitutive single crystal model for the silicon mechanical behavior: Applications to the stress induced by silicided lines and STI in MOS technologies

The control of stress in silicon devices is an important issue for improvement MOS transistor performance. Some high temperature processes, like active zone silicidation or Shallow Trench Isolation [1,2] can induce motions of dislocation just by cooling the crystal down to room temperature. In this study, a single crystal model for the silicon mechanical behavior is implemented by finite element simulation using ZeBuLong (R). The constitutive equations are taken from the well known model of Alexander and Haasen [3,4] applied to each slip along the {111} planes in the < 1 (1) over bar0 > directions. The effect of silicide-induced stress is studied and the formation of defects in silicon during the cooling is discussed. Then, two layouts where the STI pattern is different are simulated and the results are checked against the leakage current measured.