Direct evidence of the recombination of silicon interstitial atoms at the silicon surface

In this experiment, a Si wafer containing four lightly doped B marker layers epitaxially grown by CVD has been implanted with 100 keV Si+ ions to a dose of 2 x 1014 ions/cm2 and annealed at 850 deg. C for several times in an RTA system in flowing N2. TEM and SIMS analysis, in conjunction with a transient enhanced diffusion (TED) evaluation method based on the kick-out diffusion mechanism, have allowed us to accurately study the boron TED evolution in presence of extended defects. We show that the silicon surface plays a key role in the recombination of Si interstitial atoms by providing the first experimental evidence of the resulting Siints supersaturation gradient between the defect region and the surface. Our results indicate an upper limit of about 200 nm for the surface recombination length of Si interstitials at 850 deg. C in a N2 ambient