Electrically Detected Magnetic Resonance of Donors and Interfacial Defects in Silicon Nanowires

We report our work on the characterization by electrically detected magnetic resonance (EDMR) measurements of silicon nanowires (SiNWs) produced by different top-down processes. SiNWs were fabricated starting from SOI wafers using standard e-beam lithography and anisotropic wet etching or by metal-assisted chemical etching. Further oxidation was used to reduce the wire cross section. Different EDMR implementations were used to address the electronic wave function of donors (P) and to characterize point defects at the SiNWs/SiO2 interface. The EDMR spectra of as produced SiNWs with high donor concentration ([P] = 1018 cm-3 show a single line related to delocalized electrons. SiNWs produced on substrates with lower donor concentration ([P] < 1016 cm-3 reveal the doublet related to substitutional P in Si, as well as lines related to interfacial defects such as Pb0, Pb, E', and E'-like. The EDMR spectra of samples produced by metal-assisted chemical etching exposed to post production oxidation reveal a disordered and defective interface and the disappearance of the P related signal. Forming gas annealing, on the other hand, reduces the contribution of interfacial defects and allows a better resolution of the P related doublet.