Radical-Beam-Induced Surface Reaction Processes of Porous Si

A new-low temperature dry oxidation process, unlike the presently used methods of wet chemical processing or high-temperature rapid thermal annealing, for the oxidation of porous silicon (PS) is described. In this process the active oxygen radical species from an electron cyclotron resonance plasma were employed for the first time to achieve room-temperature oxidation of PS. This process allows manipulation of the PS surface chemistry which has resulted in both the enhancement and stabilization of the photoluminescence (PL) intensity. These results are explained on the basis of a proposed model in which surface-induced processes incorporate oxygen atoms not only in the outermost Si–O–Si layer but also in the backbonded Si of PS. Furthermore, it is shown that this backbond oxidation is the main mechanism responsible for the enhancement and stabilization of the PL intensity.