Structural analysis of amorphous Si films prepared by magnetron sputtering

A study is presented on the structural changes occurring in thin amorphous silicon (a-Si) during thermal treatments. The a-Si films were deposited on single-crystalline Si substrates held at room temperature by magnetron sputtering of a Si target in pure Ar atmosphere, and therefore the films were hydrogen-free. All samples were annealed in vacuum and subsequently studied by electron paramagnetic resonance (EPR) and grazing incidence X-ray diffraction (GIXRD). A slight increase in the dangling bonds content at lower annealing temperatures, and then a strong increase of it at around 650 °C, suggested significant structural changes. The samples were also studied by grazing incidence small-angle X-ray scattering (GISAXS) which confirmed changes at the nanometric scale attributed to voids in the material. A nice correlation of the results of the three techniques shows advantages of this approach in the analysis of structural changes in a-Si material.