 In general, these variants may be differentiated and classified in terms of architecture (planar vs. non-planar design) and the number of channels/gates (2, 3, or 4).A planar double-gate MOSFET (DGMOS) employs conventional planar (layer-by-layer) manufacturing processes to create double-gate MOSFET (metal-oxide-semiconductor field-effect transistor) devices, avoiding more stringent lithography requirements associated with non-planar, vertical transistor structures.In planar double-gate transistors the drain–source channel is sandwiched between two independently fabricated gate/gate-oxide stacks.