CHARACTERIZATION BY ATOMIC-FORCE MICROSCOPY OF THE SOI LAYER TOPOGRAPHY IN LOW-DOSE SIMOX MATERIALS

Because interfaces have important implication for processing and devic e performances, atomic force microscopy (AFM) has been used to investi gate both the (100) Si surface morphology and the topography of the bu ried oxide-silicon overlayer interface of low-dose separation by impla nted oxygen (SIMOX) materials. The mean roughness measured on the sili con overlayer surface is about 0.5 nm, and is flattened by a factor tw o when using additionnal annealing steps. A square-mosaic rugged morph ology has been observed on the buried oxide-silicon overlayer interfac e of samples annealed at 1320 degrees C for 6 h under an Ar-O-2 atmosp here. This morphology has been related to the interface regrowth of th e implantation-damaged silicon. These square structures have a root-me an-square (r.m.s.) height of 1-3 nm, and are flattened during addition al annealing steps at 1320 degrees C under Ar-O-2. Nanometer scale inv estigations by AFM have been used to analyse the microstructural chang es found on the silicon-on-insulator (SOI) layer after additional anne aling steps. (C) 1997 Elsevier Science S.A.