Roughness of the silicon (001)/SiO2 interface

We use synchrotron x-ray diffraction to characterize the roughness of the buried Si(001)/SiO2 interface, for three types of oxide, without modification of the interface. We show that the thermal oxide interface is 0.5±0.1 times as rough as the native oxide interface, suggesting that the oxide growth decreases the roughness slightly. We also measure the roughness of a chemically grown oxide interface.