Vertical transistors and methods of manufacturing vertical transistors are disclosed. The method can include forming a stack of layers include a first layer stack of a first transistor structure including at least three layers of a conductive material separated by one or more layers of at least one dielectric material. The stack of layers can include a second layer stack of a second transistor structure including at least three layers of a conductive material separated by one or more layers of at least one dielectric material, the second layer stack associated with a second transistor structure. The first and second transistor structures are separated by one or more dielectric materials. The method can include forming a channel opening in the stack. The method includes selectively forming a first channel structure within the channel opening and selectively forming a second channel structure within the channel opening.