ESR studies of ion implanted phosphorus donors near the Si-SiO2 interface

TL;DR

This study uses ESR to investigate phosphorus donors implanted near the Si-SiO2 interface, revealing effects of interface quality on donor activation and hyperfine signals, with implications for silicon-based quantum devices.

Contribution

It provides new insights into how the Si-SiO2 interface affects phosphorus donor activation and ESR signals in silicon.

Findings

High implant recoveries with 14 keV phosphorus ions.

Donor hyperfine signals are suppressed near the Si-SiO2 interface.

H-passivation improves donor hyperfine signal levels.

Abstract

This work reports an ESR study of low energy, low fluence phosphorus ion implantation into silicon in order to observe the activation of phosphorus donors placed in close proximity to the Si-SiO2 interface. Electrical measurements, which were used to estimate donor activation levels, reported high implant recoveries when using 14 keV phosphorus ions however, it was not possible to correlate the intensity of the hyperfine resonance signal with the electrical measurements in the presence of an SiO2 interface due to donor state ionisation (i.e. compensation effects). Comparative measurements made on silicon with an H-passivated surface reported higher donor hyperfine signal levels consistent with lower surface defect densities at the interface.