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

Ellipsometric and capacitance-voltage measurements were combined to detect both the AlSiO₂ interlayer and the SiSiO₂ interlayer for the Si/SiO₂/Al system. The AlSiO₂ interlayer was characterized by Auger electron spectroscopy (AES), combined with argon ion sputter profiling, of the Al/SiO₂/Si structure and also of the remaining SiO₂/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 SiO₂ constant. The results of these experiments indicate that the Alz.sbnd;SiO₂ 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.