Abstract: A semiconductor device includes a conductive pattern and a spacer structure disposed on a side surface of the conductive pattern. The spacer structure includes an inner spacer in contact with the side surface of the conductive pattern, an outer spacer spaced apart from the side surface of the conductive pattern, and an air gap disposed between the inner spacer and the outer spacer. The inner spacer includes an inner oxidized region exposed by the air gap. A concentration of oxygen in the inner oxidized region has a gradient in which the oxygen concentration decreases in a direction away from the air gap.

Abstract: A fuel cell stack is provided that includes: i) a plurality of unit cells that are stacked together; ii) end plates that are each disposed at outermost ends of the unit cells and that press the plurality of unit cells together; and iii) a plurality of tension bars that engage the end plates, wherein an tension bar corresponding to an outermost portion of the unit cells has a predetermined angle of slope and engages with the end plate.

Abstract: Disclosed herein is a fuel cell stack. The fuel cell stack includes: at least one unit stack comprising an assembly of unit cells and an enclosure protecting the unit stack. In particular, reaction gas inlet/outlet channels for supplying reaction gas to the unit stack are formed on a first side surface of the enclosure, and coolant inlet/outlet channels for supplying coolant to the unit stack are formed on a second side surface of the enclosure.

Abstract: A fuel cell stack is provided that includes: i) a plurality of unit cells that are stacked together; ii) end plates that are each disposed at outermost ends of the unit cells and that press the plurality of unit cells together; and iii) a plurality of tension bars that engage the end plates, wherein an tension bar corresponding to an outermost portion of the unit cells has a predetermined angle of slope and engages with the end plate.