ULTRA SMALL SIZE VERTICAL MOSFET DEVICE AND FABRICATION METHOD OF THE MOSFET DEVICE

摘要

PURPOSE: An ultra small size vertical MOSFET device and fabrication method of the MOSFET device is provided to be capable of forming an ultra-fine vertical channel by using an SOI(Silicon On Insulator) substrate without using a lithographic processing. CONSTITUTION: A first silicon conductive layer(31) is formed by doping heavily doped dopants into an SOI substrate. After sequentially forming a lightly doped silicon layer and a heavily doped second silicon conductive layer on the first silicon conductive layer(31), the silicon layer and the second silicon conductive layer are vertically etched. After forming a gate oxide(70) on the resultant structure, the heavily doped impurities in the first and second silicon conductive layers are diffused to the silicon layer, thereby simultaneously forming a source (140), a channel(41) and a drain(90) having a vertical structure. Then, a gate electrode(101) is formed at both sidewalls of the vertical structure.