Self-Diffusion in Intrinsic and Extrinsic Silicon Using Isotopically Pure³⁰Silicon/Natural Silicon Heterostructures

Abstract

Silicon self-diffusion coefficients were measured in intrinsic and extrinsic silicon from 870 to 1070°C using isotopically pure 30Si/natural Si heterostructures. 30Si diffusion profiles are determined by secondary ion mass spectrometry. The temperature dependence of intrinsic diffusion coefficient in bulk Si is obtained. Comparing it in heavily As- or B-doped Si, it is found that the fractional contribution of Si self-diffusion varies with diffusion temperatures and that different type of point defect (self-interstitial or vacancy) is supersaturated by the Fermi level effect in As- or B-doped silicon.