It was recalled that there existed contradictory reports regarding the effects of uniaxial compressive stress on boron diffusion in silicon. Some reported stress-induced retardation of boron diffusion, whereas others reported stress-induced enhancement of boron diffusion. The present work aimed to reconcile the conflicting reports on the effects of shallow trench isolation-induced compressive stress upon boron diffusion in silicon. It was proposed that there were two opposing mechanisms that affected the strain-induced change in boron diffusion. Mechanism 1, which was related to the strain-induced reduction in the silicon lattice constant, will lead to a retardation of the boron diffusion of the S/D extension implants. Mechanism 2, which was related to the formation of transient dislocations in silicon during the ramping up period of the S/D annealing, will lead to an enhancement of boron diffusion of the S/D extension implants. The interactions between the two opposing mechanisms would affect the on current versus S/D overhang characteristics as well as the off current versus S/D overhang characteristics. Similar theory could be extended to arsenic diffusion.

Mechanism Behind the Stress-Induced Change in Boron and Arsenic Diffusion in Silicon Devices and its Experimental Verification. W.S.Lau, K.S.See, P.Yang: Physica Status Solidi A, 2011, 208[4], 955–61