Electron transport in a single silicon quantum dot structure using a vertical silicon probe

We have prepared nanocrystalline-Si (nc-Si) dots with a diameter of 6/spl plusmn/2 nm using very high frequency plasma decomposition of SiH/sub 4/. For future device applications, the electrical measurement of a single dot is necessary. For that purpose, we propose a vertical silicon probe. We fabricate a vertical silicon probe from SiO/sub 2/ (30 nm)/n-Si (0.002 /spl Omega/cm). By electron-beam lithography and electron-cyclotron-resonance reactive-ion-etching (ECR-RIE), holes in the SiO/sub 2/ with a size of 30 nm/spl times/30 nm are made. Then, nc-Si dots with a density of 10/sup 12//cm/sup 2/ are deposited on the chip. The tapered shape of the holes allows one of dots to occupy the bottom opening and prevents the top electrode from contacting the bottom directly. Finally, a-Si with phosphorous doping is deposited by chemical vapor deposition (CVD), and is crystallized to form poly-Si by solid phase crystallization (SPC). As this method allows a large grain size, electrons are prevented from being trapped at grain boundaries. The good coverage makes it possible to measure a single dot in various environments.