Formation of SIMOX–SOI structure by high-temperature oxygen implantation

Abstract

We have performed oxygen ion implantation in silicon at very high substrate-temperatures (⩽1000°C) for the purpose of forming silicon-on-insulator (SOI) structure. We have expected that the high-temperature implantation can effectively avoids ion-beam-induced damages in the SOI layer and simultaneously stabilizes the buried oxide (BOX) and SOI-Si layer. Such a high-temperature implantation makes it possible to reduce the post-implantation annealing temperature. In the present study, oxygen ions with 180keV are incident on Si(001) substrates at various temperatures from room temperature (RT) up to 1000°C. The ion-fluencies are in order of 1017–1018ions/cm2. Samples have been analyzed by atomic force microscope, Rutherford backscattering, and micro-Raman spectroscopy. It is found in the AFM analysis that the surface roughness of the samples implanted at 500°C or below are significantly small with mean roughness of less than 1nm, and gradually increased for the 800°C-implanted sample. On the other hand, a lot of dents are observed for the 1000°C-implanted sample. RBS analysis has revealed that stoichiometric SOI-Si and BOX-SiO2 layers are formed by oxygen implantation at the substrate temperatures of RT, 500, and 800°C. However, SiO2-BOX layer has been desorbed during the implantation. Raman spectra shows that the ion-beam-induced damages are fairly suppressed by such a high-temperatures implantation.