Functionalization of SiO2 surfaces for Si monolayer doping with minimal carbon contamination

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van Druenen, Maart
Collins, Gillian
Glynn, Colm
O'Dwyer, Colm
Holmes, Justin D.
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American Chemical Society
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Monolayer doping (MLD) involves the functionalization of semiconductor surfaces followed by an annealing step to diffuse the dopant into the substrate. We report an alternative doping method, oxide-MLD, where ultrathin SiO2 overlayers are functionalized with phosphonic acids for doping Si. Similar peak carrier concentrations were achieved when compared with hydrosilylated surfaces (∼2 × 1020 atoms/cm3). Oxide-MLD offers several advantages over conventional MLD, such as ease of sample processing, superior ambient stability, and minimal carbon contamination. The incorporation of an oxide layer minimizes carbon contamination by facilitating attachment of carbon-free precursors or by impeding carbon diffusion. The oxide-MLD strategy allows selection of many inexpensive precursors and therefore allows application to both p- and n-doping. The phosphonic acid-functionalized SiO2 surfaces were investigated using X-ray photoelectron spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy, whereas doping was assessed using electrochemical capacitance voltage and Hall measurements.
Carbon contamination , Covalent functionalization , Doping , Monolayer , Phosphonic acids , Silicon , Stability , X-ray photoelectron spectroscopy
van Druenen, M., Collins, G., Glynn, C., O’Dwyer, C. and Holmes, J. D. (2018) 'Functionalization of SiO2 Surfaces for Si Monolayer Doping with Minimal Carbon Contamination', ACS Applied Materials & Interfaces, 10(2), pp. 2191-2201. doi:10.1021/acsami.7b16950
© 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see