It was noted that, by placing vacancy and interstitial defects at various depths, it was possible to enhance or retard B diffusion and thereby effect the formation of shallow p+n junctions. After pre-implanting 50 or 500keV Si+ ions in order to produce a vacancy-rich surface region, a study was made of the diffusion of deposited B on pre-damaged samples during annealing (900 to 1010C). There was B-diffusion retardation, for both implantation conditions, after low-temperature annealing. Enhancement occurred in a 50keV-implanted sample at high temperatures. The use of high-energy implantation to separate vacancies and interstitials could significantly reduce B diffusion. Such suppression became more obvious at higher implantation doses.

Retardation of Boron Diffusion in Silicon by Defect Engineering. L.Shao, X.Lu, X.Wang, I.Rusakova, J.Liu, W.K.Chu: Applied Physics Letters, 2001, 78[16], 2321-3