US Patent 11930637 Confined charge trap layer

Described is selective deposition of a silicon nitride (SiN) trap layer to form a memory device. A sacrificial layer is used for selective deposition in order to permit selective trap deposition. The trap layer is formed by deposition of a mold including a sacrificial layer, memory hole (MH) patterning, sacrificial layer recess from MH side, forming a deposition-enabling layer (DEL) on a side of the recess, and selective deposition of trap layer. After removing the sacrificial layer from a slit pattern opening, the deposition-enabling layer (DEL) is converted into an oxide to be used as blocking oxide.