Self-aligned split-gate nonvolatile memory structure and a method of making the same

摘要

Provided are non-volatile split-gate memory cells having self-aligned floating gate and the control gate structures and exemplary processes for manufacturing such memory cells that provide improved dimensional control over the relative lengths and separation of the split-gate elements. Each control gate includes a projecting portion that extends over at least a portion of the associated floating gate with the size of the projecting portion being determined by a first sacrificial polysilicon spacer that, when removed, produces a concave region in an intermediate insulating structure. The control gate is then formed as a polysilicon spacer adjacent the intermediate insulating structure, the portion of the spacer extending into the concave region determining the dimension and spacing of the projecting portion and the thickness of the interpoly oxide (IPO) separating the upper portions of the split-gate electrodes thereby providing improved performance and manufacturability.