A vertical Field Effect Transistor (FET) that may be an N-type FET (NFET) or a P-type FET (PFET); a multi-device vertical structure that may be two or more NFETs or two or more PFETS; logic gates including at least one vertical FET or at least one multi-device vertical; a Static Random Access Memory (SRAM) cell and array including at least one vertical FET; a memory array including at least one such SRAM cell; and the process of forming the vertical FET structure, the vertical multi-device (multi-FET) structure, the logic gates and the SRAM cell. The vertical FETs are epitaxially grown layered stacks of NPN or PNP with the side of a polysilicon gate layer adjacent the device's channel layer. The multi-FET structure may be formed by forming sides of two or more gates adjacent to the same channel layer or, by forming multiple channel layers in the same stack, e.g., PNPNP or NPNPN, each with its own gate, i.e., the side of a polysilicon gate layer. The SRAM cell may be radiation hardened by selectively thickening gate layers to increase storage node capacitance, providing high resistance cell wiring or by including a multi-layered gate oxide layer of NO or ONO, or by any combination thereof.