Nonvolatile memory device and method for fabricating the same
A nonvolatile memory device includes a floating gate formed over a semiconductor substrate, an insulator formed on a first sidewall of the floating gate, a dielectric layer formed on a second sidewall and an upper surface of the floating gate, and a control gate formed over the dielectric layer.
1. A nonvolatile memory device comprising:
a plurality of floating gates formed over a semiconductor substrate;
an insulator formed on a first sidewall of the plurality of floating gates;
a dielectric layer formed on a second sidewall and an upper surface of the plurality of floating gates; and
a control gate formed over the dielectric layer,
wherein the plurality of floating gates have the same critical dimension, and spaces, which are alternately provided between the plurality of floating gates, have different critical dimension.
2. The nonvolatile memory device of claim 1 , wherein the semiconductor substrate comprises a first trench aligned with the second sidewall of the plurality of floating gates and a second trench aligned with the first sidewall of the plurality of floating gates, and the insulator is formed on the first sidewall of the plurality of floating gates while the second trench is filled.
3. The nonvolatile memory device of claim 2 , further comprising an isolation layer to fill the first trench,
wherein the isolation layer has a height to expose the second sidewall of the plurality of floating gates.
4. The nonvolatile memory device of claim 1 , further comprising a tunnel insulation layer formed between the semiconductor substrate and the plurality of floating gates.
5. The nonvolatile memory device of claim 1 , wherein the insulator comprises an oxide layer.
6. The nonvolatile memory device of claim 1 , wherein the dielectric layer has an oxide-nitride-oxide (ONO) structure, with sequentially stacked oxide layer, nitride layer, and oxide layer.
7. The nonvolatile memory device of claim 1 , wherein a first space between the plurality of floating gates isolated by a second isolation layer is smaller than a first space or a third space between the plurality of floating gates isolated by a first isolation layer.
8. The nonvolatile memory device of claim 7 , wherein the first isolation layer is formed in a first trench and the second isolation layer is formed in a second trench.