US Patent 7138685 Vertical MOSFET SRAM cell

A method of forming an SRAM cell device includes the following steps. Form pass gate FET transistors and form a pair of vertical pull-down FET transistors with a first common body and a first common source in a silicon layer patterned into parallel islands formed on a planar insulator. Etch down through upper diffusions between cross-coupled inverter FET transistors to form pull-down isolation spaces bisecting the upper strata of pull-up and pull-down drain regions of the pair of vertical pull-down FET transistors, with the isolation spaces reaching down to the common body strata. Form a pair of vertical pull-up FET transistors with a second common body and a second common drain. Then, connect the FET transistors to form an SRAM cell.