US Patent 11557596 Semiconductor memory device

A semiconductor memory device includes a substrate with a cell array region, a first interface region, and a second interface region, the cell array region being provided with active regions, bit lines on the cell array region and the second interface region, dielectric patterns on top surfaces of the bit lines and extending along the top surfaces of the bit lines and further extending onto the first interface region, a device isolation pattern on the substrate, and including a first portion on the cell array region and a second portion on the first interface region, the first portion defining the active regions, the second portion being provided with first recesses, and each first recess being disposed between two adjacent dielectric patterns, and first sacrificial semiconductor patterns disposed on the first interface region and in the first recesses. The first sacrificial semiconductor patterns include polycrystalline silicon.