Thickness Determination of SiC ‐ on ‐ Si Thin Films by Anisotropic Reactive Ion Etching and Preferential Wet Etching

An accurate and relatively simple technique for measuring the thickness of thin SiC films (20-300 nm) on Si is described. The technique consists of SiC patterning by anisotropic reactive ion etching in fluorinated plasma followed by selective and crystallographically preferential wet chemical etching of the underlying Si in KOH/isopropyl solutions. This process reveals a free-standing portion of the SiC film which can be readil examined and measured by scanning electron microscopy (SEM). The location of the SiC/Si interface, which is very difficult to determine by other measurement techniques, is very distinct after the preferential etching