Fabrication of a nanosize Si-tip coated with a thin diamond-like carbon film

We have successfully fabricated a Si-tip with a nanosize radius (less than 10 nm) on a (100) silicon wafer using microfabrication techniques. About 100 nm of thermal SiO2 layer was grown as a masking film on the Si substrate. The isotropic etching characteristics of the SF6 plasma was also utilized in order to obtain a sharp post under the SiO2. Sharpening oxidation was peformed at 900 degrees C and dipping by 7:1 buffered HF was followed in order to get a nanosize tip. Finally, about 30 nm thickness of a hydrogen-free diamond-like carbon (DLC) film was deposited on top of the microfabricated tip by plasma-enhanced chemical vapour deposition at room temperature. The tip coated with a thin DLC film will be expected to give better characteristics of field emission due to the lower work function of DLC film than that of Si. The field emission current from the DLC-coated Si-tip was examined.