Mechanism of phosphorus pile-up in the Si-SiO2 interface

Abstract

Phosphorus pile-up in the polycrystalline Si-SiO2 interface has systematically been studied by using Auger in-depth profiling technique. The extent of pile-up is one order of magnitude less than that in the single crystal Si-SiO2 interface. It was found that the density of pile-up phosphorus atoms saturates in the polycrystalline system when the bulk concentration exceeds 5×1019 cm−3, despite no saturation for the single crystal Si system. This pronounced difference was interpreted in terms of the difference in the strain field present in the interface.