A Si substrate (100) was oxidized at a low temperature in inductively coupled O plasma. Interstitial O was found in the Si substrate, in the initial stage of oxidation, via infra-red measurements. The penetration depth of the interstitial O was about 4nm. An X-ray rocking curve of Si substrates exhibited a lower peak intensity due to lattice distortion by the interstitial O. The refractive index of thin oxides, below which interstitial O existed in the Si substrate, was smaller than the refractive index of thick oxides, below which no interstitial O existed. The interstitial O was found by plasma oxidation using O2 gas and N2O gas. The inductively coupled plasma oxidation using N2O gas was performed by atomic O, not by molecular O, indicating that atomic O in plasma was responsible for the incorporation of interstitial O.

Finding Interstitial Oxygen in a Si Substrate during Low-Temperature Plasma Oxidation. B.H.Kim, J.H.Ahn, B.T.Ahn: Applied Physics Letters, 2003, 82[16], 2682-4