Method for manufacturing memory cell

Abstract

A method for manufacturing memory cells is provided. First, a substrate is provided, wherein a liner layer and a material layer have already been sequentially formed on the substrate. Thereafter, a patterned mask layer is formed on the substrate. Then, the patterned mask layer is trimmed. Subsequently, a portion of the material layer, a portion of the liner layer and a portion of the substrate are removed by using the patterned mask layer as a mask to define a plurality of fin-structures in the substrate. Afterward, the patterned mask layer is removed and a plurality of isolation structures among the fin structures is formed. The surface of the isolation structures is lower than that of the fin structures. Following that, charge trapping structures are formed on the substrate, covering the fin structures. Succeeding, a portion of the charge trapping structures is removed to expose the material layer. Then, the treatment process turns the material layer into a protection layer. Subsequently, a gate is formed on the substrate and straddles the protection layer, the charge trapping structures and the fin structure. Afterward, source/drain regions are formed in the fin-structure exposed by both sides of the gate.