Control of the Sb redistribution in strained SiGe layers using point-defect injection

摘要

Sb diffusion in strained Si_(1-x)Ge_x (x=0.1 and 0.2) layers during nitridation (in NH_3, 810 deg) and oxidation (in dry O_2, 825 and 900 deg) of Si/Si_(1-x)Ge_x/Si heterostructures is measured and, subsequently, compared with that obtained for treatments in vacuum. An enhancement (V) or retardation (#eta#) of Sb diffusion in strained Si_(1-x)Ge_x after nitridation/oxidation anneals is detected. For example, 810 (NH_3) and 900 deg (O_2) anneals results in v approx 2 and #eta# approx 0.15 in strained Si_(0.9)Ge_(0.1), respectively. The retardation of Sb diffusion is attibuted to the injection of excess self-interstitials (I) and strongly indicating low interstitialcy fraction of Sb diffusion in strained Si_(1-x)Ge_x. The enhancement of Sb diffusion may be due to direct injection of vacancies (V), but only if the V diffusivities are significantly different in Si and Si_(1-x)Ge_x, or depletion of I in the strained Si_(1-x)Ge_x layers caused by the excess V concentration at the top surface of silicon layer.