Oxidation of silicon surface with atomic oxygen radical anions

The surface oxidation of silicon (Si) wafers by atomic oxygen radical anions (O- anions) and the preparation of metal-oxide-semiconductor (MOS) capacitors on the O- -oxidized Si substrates have been examined for the first time. The O- anions are generated from a recently developed O- storage-emission material of [Ca 24 Al 28 O 64 ] 4+ ·4O (C12A7-O- for short). After it has been irradiated by an O- anion beam (0.5 μA/cm 2 ) at 300 ℃ for 1-10 hours, the Si wafer achieves an oxide layer with a thickness ranging from 8 to 32 nm. X-ray photoelectron spectroscopy (XPS) results reveal that the oxide layer is of a mixture of SiO2 , Si2O3 , and Si2Odistributed in different oxidation depths. The features of the MOS capacitor of <Al electrode/SiO x /Si> are investigated by measuring capacitance-voltage (C-V) and current-voltage (I-V) curves. The oxide charge density is about 6.0 × 10 11 cm 2 derived from the C-V curves. The leakage current density is in the order of 10 6 A/cm 2 below 4 MV/cm, obtained from the I-V curves. The O anions formed by present method would have potential applications to the oxidation and the surface-modification of materials together with the preparation of semiconductor devices.