Plane-view observation technique of silicon nanowires by transmission electron microscopy

We have developed a novel technique of the plane-view transmission electron microscopy (TEM) observation of silicon (Si) nanowires by covering them fi rmly with a holding layer of Si3N4. The use of the Si3N4 holding layer is s hown to be effective to fix the fine structure of the sample without deform ation during a focused ion beam (FIB) thinning process, to protect the samp le from a high energy FIB, and to give high contrast in the TEM image of th e crystalline fine structure. The Si3N4 holding layer is quite suitable, th erefore, for plane-view TEM observation of the fine structure such as a Si nanowire. By means of the proposed observation technique, we have successfu lly observed clear features in the direction of length of narrow (16 nm) Si nanowires fabricated by using SiO2 sidewall masks and the extremely fine ( 3-5 nm) Si nanowires obtained by the successive self-limiting oxidation, Mo reover, the plane-view TEM lattice image of the ultrafine Si nanowire was a lso observed. The plane-view TEM observation technique described here is us eful to analyze various fine nanostructures and contributes to develop nano fabrication technology. (C) 1999 American Vacuum Society. [S0734-211X(99)00 205-X].