This letter reports the effect of organic matter on the growth of native oxide on a Si surface. Bare Si wafers and Si wafers with native oxide were stored under various conditions in a clean room and the thickness of native oxide was examined. In the case of the bare Si wafers, the native oxide hardly grew in a closed system but the native oxide grew to 6 Å in an open system when the storage time was 24 h. On the other hand, in the case of Si wafers with native oxide, this suggests that accumulation of organic matter occurs on Si wafers in the open system in the clean room. It was suggested that the accumulation of organic matter on Si wafers facilitates the growth of native oxide.

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Organic matter on a Si surface was investigated using thermal desorption spectroscopy (TDS). It was clarified that acetone, ethanol and toluene contaminants on a bare Si surface can be detected by the TDS system, ESCO EMD-WA1000K, and these organic contaminants have different desorption temperatures and fragment patterns. Therefore organic contaminants on Si wafers were thought to be separated by desorption temperature, and characterized from the fragment pattern at that desorption temperature. Here, the desorption temperature is thought to be proportional to the activation energy for desorption. Thus bonding strength between organic contaminants and the Si surface is qualitatively estimated from the desorption temperature.