Concepedia

Publication | Closed Access

Low temperature thermal ALD of a SiNx interfacial diffusion barrier and interface passivation layer on SixGe1− x(001) and SixGe1− x(110)

DOI

19

Citations

45

References

2017

Year

Mary Edmonds, Kasra Sardashti, Steven Wolf, Evgueni Chagarov, Max Clemons, Tyler Kent, Jun Hong Park, Kechao Tang, Paul C. McIntyre, Naomi Yoshida,
The Journal of Chemical Physics

Abstract

Atomic layer deposition of a silicon rich SiN<sub>x</sub> layer on Si<sub>0.7</sub>Ge<sub>0.3</sub>(001), Si<sub>0.5</sub>Ge<sub>0.5</sub>(001), and Si<sub>0.5</sub>Ge<sub>0.5</sub>(110) surfaces has been achieved by sequential pulsing of Si<sub>2</sub>Cl<sub>6</sub> and N<sub>2</sub>H<sub>4</sub> precursors at a substrate temperature of 285 °C. XPS spectra show a higher binding energy shoulder peak on Si 2p indicative of SiO<sub>x</sub>N<sub>y</sub>Cl<sub>z</sub> bonding while Ge 2p and Ge 3d peaks show only a small amount of higher binding energy components consistent with only interfacial bonds, indicating the growth of SiO<sub>x</sub>N<sub>y</sub> on the SiGe surface with negligible subsurface reactions. Scanning tunneling spectroscopy measurements confirm that the SiN<sub>x</sub> interfacial layer forms an electrically passive surface on p-type Si<sub>0.70</sub>Ge<sub>0.30</sub>(001), Si<sub>0.50</sub>Ge<sub>0.50</sub>(110), and Si<sub>0.50</sub>Ge<sub>0.50</sub>(001) substrates as the surface Fermi level is unpinned and the electronic structure is free of states in the band gap. DFT calculations show that a Si rich a-SiO<sub>0.4</sub>N<sub>0,4</sub> interlayer can produce lower interfacial defect density than stoichiometric a-SiO<sub>0.8</sub>N<sub>0.8</sub>, substoichiometric a-Si<sub>3</sub>N<sub>2</sub>, or stoichiometric a-Si<sub>3</sub>N<sub>4</sub> interlayers by minimizing strain and bond breaking in the SiGe by the interlayer. Metal-oxide-semiconductor capacitors devices were fabricated on p-type Si<sub>0.7</sub>Ge<sub>0.3</sub>(001) and Si<sub>0.5</sub>Ge<sub>0.5</sub>(001) substrates with and without the insertion of an ALD SiO<sub>x</sub>N<sub>y</sub> interfacial layer, and the SiO<sub>x</sub>N<sub>y</sub> layer resulted in a decrease in interface state density near midgap with a comparable C<sub>max</sub> value.

References

YearCitations

Page 1