Semiconductor devices and methods for manufacturing the same

1. A method to manufacture a semiconductor device, comprising:

selectively forming an oxide layer on only a predetermined portion of a first substrate before loading the first substrate and a second substrate into a boat;

loading the first and the second substrates alternately in a plurality of slots of the boat, wherein the first substrate is to be provided with an oxynitride layer and the second substrate has a nitride layer; and

forming the oxynitride layer on the first substrate by positioning the boat in a furnace and thermally treating the boat in an oxygen atmosphere.

2. A method as defined in claim 1 , wherein the nitride layer is on the surface of the second substrate.

3. A method as defined in claim 1 , further comprising selectively forming an oxide layer on a first predetermined position of the first substrate while not forming an oxide layer on a second predetermined portion of the first substrate before loading the first and the second substrates.

4. A method as defined in claim 1 , wherein the oxynitride layer is formed on the first substrate without adding a nitrogen-containing gas to the furnace.

5. A method as defined in claim 1 , further comprising forming a pluiality of active regions in the first substrate prior to selectively forming the oxide layer.

6. A method as defined in claim 5 , further comprising forming device isolation regions separating each of the plurality of active regions.

7. A method as defined in claim 5 , wherein selectively forming the oxide layer on only the predetermined portion of the first substrate comprises thermally oxidizing the plurality of active regions to form the oxide layer over the plurality of active regions, and removing the oxide layer from all of the plurality of active regions except in the predetermined portion of the first substrate.

8. A method as defined in claim 5 , wherein the predetermined portion of the first substrate comprises one of the plurality of active regions.

9. A method as defined in claim 8 , wherein forming the oxynitride layer on the first substrate comprises forming a first oxynitride layer over the predetermined portion and forming a second oxynitride layer on at least one of the remaining active regions of the plurality of active regions.

10. A method as defined in claim 8 , wherein the first oxynitride layer has a thickness greater than a thickness of the second oxynitride layer.

11. A method as defined in claim 8 , wherein the first oxynitride layer has a thickness substantially equal to the thickness of the oxide layer.

12. A method as defined in claim 10 , wherein the second oxynitride layer has a crystalline structure with a substantially uniform distribution of nitrogen.

13. A method as defined in claim 10 , wherein the first oxynitride layer has a crystalline structure and a concentration of nitrogen that decreases from a surface of the oxynitride layer to an interface of the oxynitride layer with the underlying predetermined portion of the first substrate.

14. A method as defined in claim 1 , wherein the first and second substrates comprise silicon.

15. A method as defined in claim 5 , wherein forming the plurality of active regions comprises:

implanting P-type ions into the first substrate to control a threshold voltage;

implanting ions into the first substrate to fix a channel; and

implanting ions into the first substrate to prevent a punch-through effect.

16. A method as defined in claim 1 , wherein thermally treating the boat in the oxygen atmosphere comprises flowing a gas mixture substantially free of nitrogen into the furnace.

17. A method as defined in claim 6 , wherein forming the device isolation regions comprise a LOCOS or a shallow trench isolation method.