Si/SiO chi, 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 x 10(-7) mbar and 8.0 x 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 similar to 1 nm thick, pseudomorph, and exhibit crystalline order throughout the layer. In addition, transmission electron microscopy shows that the oxygen concentration is laterally inhomogeneous. The rnultilayer structures are thermally very stable, as rapid thermal annealing up to 1000 degrees C shows no influence on the X-ray diffraction patterns. (C) 2013 Elsevier B.V. All rights reserved