High K dielectric film

• US 6,770,923 B2
• Filed: 03/15/2002
• Issued: 08/03/2004
• Est. Priority Date: 03/20/2001
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Nguyen, Bich-Yen, Zhou, Hong-Wei, Wang, Xiao-Ping
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US10/099,794
• Publication Number:
  US 20020137250A1
• Time in Patent Office: 872 Days
• Field of Search: 438/13, 438/573, 438/605, 438/688, 438/761, 257/344, 257/346, 257/336, 257/408, 257/411
• US Class Current: 257/295
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02192 the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material

Abstract

A dielectric layer comprises lanthanum, aluminum, nitrogen, and oxygen and is formed between two conductors or a conductor and substrate. In one embodiment, the dielectric layer is graded with among the lanthanum, nitrogen, or aluminum. An additional insulating layer may be formed between the conductor or substrate and the dielectric layer. The dielectric layer can be formed by atomic layer chemical vapor deposition, physical vapor deposition, organometallic chemical vapor deposition or pulsed laser deposition.

Claims

1. A semiconductor structure comprising:

a semiconductor substrate;

a dielectric layer comprising lanthanum, aluminum, oxygen, and nitrogen over the semiconductor substrate; and

an electrode layer over the dielectric layer.

2. The semiconductor structure of claim 1, further comprising an interfacial layer between the semiconductor substrate and the dielectric layer.

3. The semiconductor structure of claim 2 wherein the interfacial layer comprises silicon, nitrogen, and oxygen.

4. The semiconductor structure of claim 2 wherein the interfacial layer comprises aluminum, nitrogen, and oxygen.

5. The semiconductor structure of claim 1 wherein a concentration of nitrogen in the dielectric layer is higher adjacent the electrode layer as compared to adjacent the semiconductor substrate.

6. The semiconductor structure of claim 1 wherein the dielectric layer is amorphous.

7. The semiconductor structure of claim 1 wherein the semiconductor substrate is selected from a group consisting of monocrystalline silicon, gallium arsenide, semiconductor on insulator, silicon germanium, and germanium.

8. The semiconductor structure of claim 1, wherein the electrode layer is a gate electrode.

9. The semiconductor structure of claim 1 wherein at least one element of the dielectric layer is graded from zero to an amount grater than zero.

10. A semiconductor structure comprising:

a first conductive layer;

a dielectric layer comprising lanthanum, aluminum, oxygen, and nitrogen over the first conductive layer; and

a second conductive layer over the dielectric layer.

11. The semiconductor structure of claim 10, wherein the first conductive layer is a floating gate.

12. The semiconductor structure of claim 10, wherein at least one of the first conductive layer and the second conductive layer is a capacitor plate.

13. The semiconductor structure of claim 10, wherein the dielectric layer has a concentration of nitrogen which is higher in a center portion of the dielectric layer as compared to portions adjacent both the first conductive layer and the second conductive layer.

14. A semiconductor structure comprising:

a semiconductor substrate;

a first dielectric layer formed over the semiconductor substrate;

a second dielectric layer comprising lanthanum, aluminum, oxygen, and nitrogen formed over the first dielectric layer; and

an electrode layer over the dielectric layer.

15. The semiconductor structure of claim 14 wherein the first dielectric layer is less than approximately 10 angstroms (1 nanometer) thick, and the second dielectric layer is between approximately 20-90 angstroms (2-9 nanometers) thick.

16. The semiconductor structure of claim 15 wherein the first dielectric comprises one of silicon oxide, oxynitride, and aluminum oxide.

17. The semiconductor structure of claim 14 wherein the first dielectric layer is between approximately 10-90 angstroms (1-9 nanometers) thick, and the second dielectric layer is between approximately 5-20 angstroms (0.5 to 2 nanometers) thick.

18. The semiconductor structure of claim 17 wherein the first dielectric layer has a dielectric constant (K_ε

) in excess of 5.

19. A semiconductor structure, comprising

a semiconductor substrate;

and

a dielectric feature consisting of lanthanum, aluminum, nitrogen, and oxygen over the semiconductor substrate.

20. The semiconductor structure of claim 19, wherein the dielectric feature consists of nitrided lanthanum aluminate.

21. The semiconductor structure of claim 19, wherein the dielectric feature comprises one of a gate dielectric, an etch stop layer, a trench liner, and a sidewall spacer liner.

22. The semiconductor structure of claim 19, wherein the dielectric feature functions as a gate dielectric.