Multilayer structures of silicon-suboxide embedded in single crystal silicon

• Epitaxial growth of ultra-thin silicon-suboxide layers embedded in c-silicon.
• Growth of multilayer structures of Si/SiOx with up to 20 repetitions.
• Simulation method to determine oxygen content of SiOx layers.
• SiOx layers are stable thermally up to 1000 °C for 5 min.

Si/SiOx multilayer structures with ultra-thin silicon-suboxide layers are fabricated with molecular beam epitaxy. The silicon surface is oxidized during growth interruptions at an oxygen pressure between 1.0×10−7 mbar and 8.0×10−7 mbar. Overgrowth with Si of the oxidized surface is possible for coverages of a few monolayers of O and improves with increasing substrate temperature. X-ray diffraction shows that the silicon layers are single crystalline. Transmission electron microscopy measurements show that the suboxide layers are ~1nm thick, pseudomorph, and exhibit crystalline order throughout the layer. In addition, transmission electron microscopy shows that the oxygen concentration is laterally inhomogeneous. The multilayer structures are thermally very stable, as rapid thermal annealing up to 1000 °C shows no influence on the X-ray diffraction patterns.