Fabrication of silicon-on-nothing (SON) MOSFET fabrication using selective etching of Si1-xGex layer

摘要

A method for fabrication of silicon-on-nothing (SON) MOSFET using selective etching of Si_1-xGe_x layer, includes preparing a silicon substrate; growing an epitaxial Si_1-xGe_x layer on the silicon substrate; growing an epitaxial thin top silicon layer on the epitaxial Si_1-xGe_x layer; trench etching of the top silicon and Si_1-xGe_x, into the silicon substrate to form a first trench; selectively etching the Si_1-xGe_x layer to remove substantially all of the Si_1-xGe_x to form an air gap; depositing a layer of SiO₂ by CVD to fill the first trench; trench etching to from a second trench; selectively etching the remaining Si_1-xGe_x layer; depositing a second layer of SiO₂ by CVD to fill the second trench, thereby decoupling a source, a drain and a channel from the substrate; and completing the structure by state-of-the-art CMOS fabrication techniques.