| 摘要 |
Fabrication of a submicron wide single crystal silicon structure protruding from a monolithic silicon body. Starting with a single crystal N silicon body having a P region, an insulator stud of submicron width and length dictated by the limits of lithography is formed on the P region. Using the stud as a mask, the P region is etched forming the top narrow portion having the stud width projecting from the silicon body. On the exposed sides of the top portion oxide walls are formed and the etching continued forming the middle portion of a width exceeding that of the top portion. An oxide-nitride wall is established on the exposed sides of the middle portion and, using the resulting structure as a mask, the etching is continued to completely etch through the P region and a substantial portion of the underlying N silicon body thereby forming a free-standing silicon protrusion structure. Thick oxide walls are formed on the just exposed sides of the silicon. Alternatively, the exposed sides of silicon may be completely oxidized to obtain a fully dielectrically isolated silicon protruding structure. To form NPN device from the silicon protrusion structure, the oxide-nitride walls corresponding to the middle portion are removed and N-type dopant is introduced from the thus exposed sides forming the emitter and collector juxtaposed on either side of the central P-type region which functions as the base. Self-aligned metal contacts to the elements of the transistor are established on the top and sides.
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