Vertical p-MOSFETs with gate oxide deposition before selective epitaxial growth

A novel vertical MOSFET concept using selective epitaxial growth by low pressure chemical vapor deposition is proposed and the ®rst p-channel device characteristics measured are described. In contrast to other MOS technologies, the gate oxide is deposited before epitaxy, and therefore it exists before the channel region is grown. Compared to planar layouts, the vertical layout increases the packing density without the use of advanced lithography; the extent of the increase depends on application. Compared to other vertical transistors, this concept reduces overlap capacitance and o ers the possibility of three-dimensional integration. Vertical p channel MOSFETs with a channel length LG down to 130 nm and a gate oxide thickness dox down to 12 nm have been fabricated and yield a transconductance of 100 mS mm-1.