| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor memory device superior in flatness of the capacitor lower electrode by making lower steps on the surface of a barrier layer than those on the top ends of contact holes. SOLUTION: Polysilicon is deposited on an interlayer insulation film 11 having contact holes 11a and etched to form polysilicon plugs 12 in these holes with steps h1 defined by the top ends of the plugs 12 and those of the contact holes 11a. Barrier metal layers 13a, 13b are formed to cover the surface of the plugs 12 and that of the insulation film 11 and heat treated in a nitrogen gas atmosphere to expand the vol. to form a nitride film. This reduces the steps h2 defined by the top ends of the contact holes 11a and those of the barrier metal layers, compared with the steps h1 . |
