MOS transistor and method of manufacturing the same
View Patent ↗An object of the present invention is to provide a MOS transistor of a new structure and a method of manufacturing the same that is capable of easily fabricating a high integration density device by overcoming photolithography limitations. The object of the present invention is accomplished by a MOS transistor, including a semiconductor substrate having a projection in which the width of an upper portion thereof is larger than that of a lower portion thereof; an isolating layer formed in the middle of substrate of the projection; first and second drain regions formed within the surface of the substrate of the projection; first and second source regions formed within the surface of the substrate on both sides of the projection; a gate insulating layer formed on the entire surface of the substrate; and first and second gates formed on the gate insulating layer on both sides of the substrate of the projection.
1. A method of manufacturing a MOS transistor, comprising:
forming an isolating layer in a semiconductor substrate;
forming first and second drain regions in the surface of the substrate on both sides of the isolating layer;
etching the portions of the first and second drain regions and the substrate on both sides of the isolating layer to form a projection having the isolating layer in its middle;
forming a spacer on the sidewalls of the substrate of the projection;
forming a barrier layer on the surfaces of the first and second drain regions and of the substrate on both sides of the projection; selectively removing the spacer;
forming first and second recesses by etching the substrate exposed by the barrier layer;
removing the barrier layer;
forming a gate insulating layer on the entire surface of the substrate;
forming first and second source regions within the surface of the substrate on both sides of the projection;
depositing a gate material layer on the gate insulating layer so as to fill the first and second recesses; and
forming first and second gates on the gate insulating layer on both sides of the substrate of the projection by patterning the gate material layer.
2. The method of claim 1 , wherein the isolating layer is a deep trench type.
3. The method of claim 2 , wherein the depth of the isolating layer is larger than the height of the projection.
4. The method of claim 1 , wherein the spacer is formed of a nitride layer.
5. The method of claim 4 , wherein the spacer is removed by wet etching.
6. The method of claim 1 , wherein the barrier layer is formed of a silcide layer.
7. The method of claim 1 , wherein the etching is performed by isotropic etching at the forming of the first and second recesses.
8. The method of claim 7 , wherein the isotropic etching is performed by wet etching or dry etching.
9. The method of claim 8 , wherein the dry etching is performing by injecting etch gas at the angle of inclination to the substrate.
10. The method of claim 1 , wherein the gate material layer is formed of a polysilicon layer.