VERTICAL GATE TOP ENGINEERING FOR IMPROVED GC AND CB PROCESS WINDOWS

摘要

A method for a memory cell has a trench capacitor and a vertical transistor adjacent to the capacitor. The vertical transistor has a gate conductor above the trench capacitor. The upper portion of the gate conductor is narrower than the lower portion of the gate conductor. The memory cell further includes spacers adjacent the upper portion of the gate conductor and a bitline contact adjacent to the gate conductor. The spacers reduce short circuits between the bitline contact and the gate conductor. The gate contact above the gate conductor has an insulator which separates the gate contact from the bitline. The difference between the width of the upper and lower portions of the gate conductor reduces short circuits between the bitline contact and the gate conductor.