METHOD TO REDUCE TRENCH CAPACITOR LEAKAGE FOR RANDOM ACCESS MEMORY DEVICE

摘要

A method is provided that includes forming a trench isolation structure in a dynamic random memory region (DRAM) of a substrate and patterning an etch mask over the trench structure to expose a portion of the trench structure. A portion of the exposed trench structure is removed to form a gate trench that includes a first corner formed by the substrate and a second corner formed by the trench structure. The etch mask is removed and the first corner of the gate trench is rounded to form a rounded corner. This is followed by the formation of an oxide layer over a sidewall of the gate trench, the first rounded corner, and the semiconductor substrate adjacent the gate trench. The trench is filled with a gate material.