(Invited) Ballistic Electron Emission from Nanosilicon Diode and its Application to Ultra-Thin Film Deposition of Silicon and Germanium

A novel wet fabrication technique of quantum-scale Si and Ge thin films is presented based on the ballistic electron effect in solutions. A nanocrystalline silicon (nc-Si) diode, composed of a thin Au (10 nm), nc-Si layer (~1 µm), polycrystalline silicon, and n+-Si substrate, generates ballistic electrons via a multiple-tunneling cascade through a chain of nc-Si dots interconnected with tunnel oxides and ejects energetic electrons from the device surface. A remarkable function of is this nc-Si ballistic emitter is that it operates even in solutions as a supplier of highly reducing electrons. When driven in SiCl4 and GeCl4 solutions without the use of counter electrodes the reducing activity of injected electrons induces the deposition of thin amorphous Si and Ge films on the emission area without producing any by-products and contaminations. Following a brief description of the ballistic emission, the characteristic features of the observed electro-reduction deposition mode is discussed.