US Patent 9627405 Semiconductor device and manufacturing method thereof

A semiconductor device may include a multi-layered source layer, conductive patterns, interlayer insulating layers, and a channel pillar. The multi-layered source layer may include a lower source layer, an interlayer source layer, and an upper source layer. The conductive patterns and interlayer insulating layers may be alternately disposed on the multi-layered source layer. The channel pillar may penetrate the conductive patterns. The interlayer insulating layers, the upper source layer, and the interlayer source layer, the channel pillar may extend into the lower source layer. The channel pillar may be in contact with the interlayer source layer. Doped regions having various structures can be formed at a lower portion of the channel pillar, thereby improving the operational reliability of the semiconductor device.