Semiconductor device and method of manufacturing the same
View Patent ↗A semiconductor device includes a substrate including a plurality of active regions divided by a plurality of trenches, a plurality of tunnel insulating layer patterns formed over the active regions, a plurality of conductive film patterns formed over the tunnel insulating film patterns, a plurality of first isolation layers formed on sidewalls and bottom surfaces of the trenches, and a plurality of second isolation layers formed between the conductive film patterns.
1. A method of manufacturing a semiconductor device, the method comprising:
stacking a tunnel insulating layer and a first conductive film over a substrate including a plurality of alternately disposed first and second regions, wherein the substrate is formed of a single crystalline silicon;
etching the first conductive film, the tunnel insulating layer and the second regions of the substrate to form tunnel insulating film patterns and first conductive film patterns over the first regions and to form trenches in the second regions, wherein the first conductive film is formed of a polycrystalline silicon; and
simultaneously forming first isolation layers and second isolation layers over the surfaces of the trenches which expose a portion of the substrate and between the first conductive film patterns to form air gaps within the trenches by an oxidation process using a mixture of H 2 gas and O 2 gas,
wherein the second isolation layers grow faster than the first isolation layers,
wherein first and second isolation layers of the plurality of first and second isolation layers are formed to make the air gaps in spaces surrounded by the first and second isolation layers, and
wherein each of the air gaps has a T-shaped cross-section taken in a direction crossing active regions of the substrate.
2. The method of claim 1 , wherein the oxidation process is performed at a temperature between 700° C. and 800° C. by mixing the H 2 gas and the O 2 gas in a ratio of 1:1.
3. The method of claim 1 , wherein the first isolation layers are formed along surfaces of the first regions, and
the second isolation layers are spaced apart from the first isolation layers and formed between the first conductive film patterns.
4. The method of claim 3 , wherein the first isolation layers include an oxidized portion of the first regions and an oxide film grown on the oxidized portion of the first regions.
5. The method of claim 3 , wherein the second isolation layers include an oxidized portion of sidewalls of the first conductive film patterns and an oxide film grown on the oxidized portion of the sidewalls of the first conductive film patterns.
6. The method of claim 1 , wherein the forming of the trenches comprises:
forming isolation masks to block the first regions and open the second regions; and
etching the first conductive film, the tunnel insulating layer, and the substrate in regions opened by the isolation masks.
7. The method of claim 6 , further comprising:
removing the isolation masks after the forming of the first and second isolation layers.
8. The method of claim 1 , further comprising:
after the forming of the first and second isolation layers,
forming a dielectric film over the surfaces of the second isolation layers and the first conductive film patterns;
forming a second conductive film over the dielectric film;
forming gate masks in a direction crossing the first regions over the second conductive film; and
etching the second conductive film, the dielectric film, and the first conductive film patterns of the regions exposed through the gate masks.
9. The method of claim 1 , further comprising:
after the forming of the first and second isolation layers,
etching the second isolation layers so that sidewalls of the first conductive film patterns are exposed.