Semiconductor devices, memory dies and related methods

Abstract

A semiconductor substrate is provided. Active areas and trench isolation regions are formed. The active areas extend along a first direction. Buried word lines extending along a second direction are formed in the semiconductor substrate. Two of the buried word lines intersect with each of the active areas, separating each of the active areas into a digit line contact area and two cell contact areas. Buried digit lines extending along a third direction are formed above the buried word lines. An upper portion of the trench isolation region is removed to form an L-shaped recessed area around each of the cell contact areas. The L-shaped recessed area exposes sidewalls of the cell contact areas. An epitaxial silicon growth process is then performed to grow an epitaxial silicon layer from the exposed sidewalls and a top surface of each of the cell contact areas, thereby forming enlarged cell contact areas.