Two-dimensional profiling and size effects on the transient enhanced diffusion of ultralow-energy B implants in Si

Two-dimensional profiles of ultralow-energy B implants in Si after diffusio n have been studied in detail by scanning capacitance microscopy in connect ion with a double beveling technique to enhance depth and lateral resolutio n. Implants have been made into patterned wafers with different feature siz es ranging from 0.8 to 5 mum. It is demonstrated that the B transient enhan ced diffusion is strongly reduced with decreasing feature size below about 2 mum. This effect is related to the increasing effect of interstitial late ral out-diffusion under the SiO2 mask. The implication for the formation of ultrashallow junctions in device structures is discussed. (C) 2001 America n Institute of Physics.