Method for processing a semiconductor device comprising a silicon-oxy-nitride dielectric layer
View Patent ↗The present invention provides a method for processing a semiconductor device wherein a dielectric layer is partially converted into a silicon-oxy-nitride by incorporation of nitrogen atoms into the dielectric layer, which comprises a silicon oxide. Before the introduction of the nitrogen atoms into the dielectric layer, the dielectric layer is provided as a silicon oxide in which the atomic silicon to oxygen ration is greater than ½. In this way, MOS transistors are obtained with a high quality interface between the dielectric region and semiconductor substrate, and a dielectric region which is impermeable to impurity atoms from the gate region and which has a thickness which is substantially equal to the dielectric layer as deposited.
1. A method for processing a semiconductor device comprising a silicon oxide control electrode dielectric layer and a control electrode, the method comprising:
forming a control electrode dielectric layer on a semiconductor substrate, the control electrode dielectric layer comprising a silicon oxide, wherein at least a portion of the silicon oxide has an atomic silicon to oxygen ratio that is greater than 0.5, the step of forming the control electrode dielectric layer comprising:
forming a first region of the control electrode dielectric layer, wherein the first region is positioned adjacent to an interface between the semiconductor substrate and the control electrode dielectric layer, and wherein the first region has an atomic silicon to oxygen ratio substantially equal to ½;
forming a second region of the control electrode dielectric layer, wherein the second region is positioned adjacent to a surface of the control electrode dielectric layer, wherein the second region has an atomic silicon to oxygen ratio larger than ½;
forming a third region of the control electrode dielectric layer with an atomic silicon to oxygen ratio substantially equal to ½ atop the control electrode dielectric layer;
incorporating additional silicon atoms into the control electrode dielectric layer by implantation;
converting a portion of the control electrode dielectric layer into a silicon-oxy-nitride layer by incorporating nitrogen atoms into the control electrode dielectric layer; and thereafter
forming the control electrode on top of the control electrode dielectric layer.
2. The method according to claim 1 , wherein an atomic silicon to oxygen ratio in the control electrode dielectric layer gradually decreases from the second region towards the first region, from a value greater than ½ to a value substantially equal to ½.
3. The method according to claim 1 , wherein the substrate comprises silicon, and wherein forming a control electrode dielectric layer comprises performing a thermal oxidation of the substrate.
4. The method according to claim 1 , wherein forming a control electrode dielectric layer comprises performing a deposition.
5. The method according to claim 4 , wherein forming a control electrode dielectric layer comprises performing a chemical vapor deposition.
6. The method according to claim 1 , wherein incorporating nitrogen atoms in the control electrode dielectric layer is performed using a nitrogen plasma.
7. A method for processing a semiconductor device comprising a silicon oxide control electrode dielectric layer and a control electrode, the method comprising:
forming a control electrode dielectric layer on a semiconductor substrate, the control electrode dielectric layer comprising a silicon oxide, wherein at least a portion of the silicon oxide has an atomic silicon to oxygen ratio that is greater than 0.5, the step of forming the control electrode dielectric layer comprising:
forming a first region of the control electrode dielectric layer, wherein the first region is positioned adjacent to an interface between the semiconductor substrate and the control electrode dielectric layer, and wherein the first region has an atomic silicon to oxygen ratio substantially equal to ½; and
forming a second region of the control electrode dielectric layer, wherein the second region is positioned adjacent to a surface of the control electrode dielectric layer, wherein the second region has an atomic silicon to oxygen ratio larger than ½, and wherein an atomic silicon to oxygen ratio in the control electrode dielectric layer gradually decreases from the second region towards the first region, from a value greater than ½ to a value substantially equal to ½;
forming a third region of the control electrode dielectric layer with an atomic silicon to oxygen ratio substantially equal to ½;
incorporating additional silicon atoms into the control electrode dielectric layer by implantation;
converting a portion of the control electrode dielectric layer into a silicon-oxy-nitride layer by incorporating nitrogen atoms into the control electrode dielectric layer; and thereafter
forming the control electrode on top of the control electrode dielectric layer.
8. The method according to claim 7 , wherein the substrate comprises silicon, and wherein forming a control electrode dielectric layer comprises performing a thermal oxidation of the substrate.
9. The method according to claim 7 , wherein forming a control electrode dielectric layer comprises performing a deposition.
10. The method according to claim 9 , wherein forming a control electrode dielectric layer comprises performing a chemical vapor deposition.
11. The method according to claim 7 , wherein incorporating nitrogen atoms in the control electrode dielectric layer is performed using a nitrogen plasma.
12. A semiconductor device comprising a control electrode on top of a control electrode dielectric layer on a semiconductor substrate, wherein the control electrode dielectric layer is at least partially a silicon-oxy-nitride layer, and wherein the control electrode dielectric layer comprises:
a first region, wherein the first region is positioned adjacent to an interface between the semiconductor substrate and the control electrode dielectric layer, wherein the first region has an atomic silicon to oxygen ratio substantially equal to ½; and
a second region, wherein the second region is positioned adjacent to a surface of the control electrode dielectric layer, wherein the second region has an atomic silicon to oxygen ratio greater than ½; and
a third region atop the control electrode dielectric layer with an atomic silicon to oxygen ratio substantially equal to ½.
13. A semiconductor device according to claim 12 , wherein the semiconductor substrate comprises silicon.
14. A semiconductor device according to claim 12 , wherein the semiconductor device comprises a transistor device.
15. A semiconductor device according to claim 12 , wherein the silicon-oxy-nitride layer is situated in the second region.
16. A semiconductor device comprising a control electrode on top of a control electrode dielectric layer on a semiconductor substrate, wherein the control electrode dielectric layer is at least partially a silicon-oxy-nitride layer, and wherein the control electrode dielectric layer comprises:
a first region positioned adjacent to an interface between the semiconductor substrate and the control electrode dielectric layer, wherein the first region has an atomic silicon to oxygen ratio substantially equal to ½;
a second region positioned adjacent to a surface of the control electrode dielectric layer, wherein the second region has an atomic silicon to oxygen ratio larger than ½, and wherein an atomic silicon to oxygen ratio in the control electrode dielectric layer gradually decreases from the second region towards the first region, from a value greater than ½to a value substantially equal to ½; and
a third region with an atomic silicon to oxygen ratio substantially equal to ½.
17. A semiconductor device according to claim 16 , wherein the semiconductor substrate comprises silicon.
18. A semiconductor device according to claim 16 , wherein the semiconductor device comprises a transistor device.
19. A semiconductor device according to claim 16 , wherein the silicon-oxy-nitride layer is situated in the second region.