Abstract: A volatile memory device and a nonvolatile memory device are provided. Provided is a plurality of gate electrodes and a plurality of insulating patterns alternately stacked on top of each other in a first direction, an information storage film formed along a sidewall of a trench, wherein the trench extends through the plurality of gate electrodes and the insulating patterns in the first direction, and a semiconductor pattern formed on the information storage film, wherein the semiconductor pattern is made of polycrystalline silicon composed of a first monocrystalline silicon and a second monocrystalline silicon, wherein a metal silicide is present in a grain boundary between the first monocrystalline silicon and the second monocrystalline silicon, wherein the metal silicide is absent in each of the first monocrystalline silicon and the second monocrystalline silicon except for the grain boundary therebetween.

Abstract: Disclosed is a small lens system including a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from an object, wherein the clear aperture of an object-side surface L1S1_CA (clear aperture) and the clear aperture of an image-side surface L1S2_CA (clear aperture) of the first lens satisfy 1<L1S2_CA/L1S1_CA<1.2.

Abstract: Disclosed is a small wide-angle lens system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens sequentially arranged from an object, wherein the first lens has a convex object-side surface, the third lens has a negative refractive power, the fourth lens has a concave image-side surface, the sixth lens has a concave object-side surface and a concave image-side surface, the ninth lens has a negative refractive power and a concave object-side surface, all surfaces of the first to ninth lenses are aspherical surfaces, the refractive power P1 of the first lens satisfies |P1|<0.01, and Fno of the lens system satisfies Fno <1.6.