Measurement of the interlayer between aluminum and silicon dioxide using ellipsometric, capacitance-voltage and auger electron spectroscopy techniques

Abstract

Ellipsometric and capacitance-voltage measurements were combined to detect both the AlSiO 2 interlayer and the SiSiO 2 interlayer for the Si/SiO 2/Al system. The AlSiO 2 interlayer was characterized by Auger electron spectroscopy (AES), combined with argon ion sputter profiling, of the Al/SiO 2/Si structure and also of the remaining SiO 2/Si structure after the aluminum had been chemically removed. An effective interlayer thickness is defined as the product of the interlayer thickness and the fractional change in the dielectric SiO 2 constant. The results of these experiments indicate that the Alz.sbnd;SiO 2 effective interlayer thickness has a range of 0.1–0.5 nm. The AES data can be readily interpreted if it is assumed that collision cascade mixing and recoil implantation occur as a consequence of sputter depth profiling through the aluminum.