Multilayer structure used especially as a material of high relative permittivity

• US 6,713,199 B2
• Filed: 12/24/2002
• Issued: 03/30/2004
• Est. Priority Date: 12/31/2001
• Status: Expired due to Term

• Current Assignee: Sakura Technologies, LLC
• Original Assignee: Memscap Incorporated
• Inventors: Girardie, Lionel
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): MCNEIL, JENNIFER C
• Application Number:
  US10/329,115
• Publication Number:
  US 20030124394A1
• Time in Patent Office: 462 Days
• Field of Search: 428/697, 428/699, 428/701, 428/702, 428/469, 428/472.1, 428/472.2, 428/688, 428/689, 428/332, 428/336
• US Class Current: 428/701
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• 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: Y10T 428/265 1 mil or less

Abstract

A multilayer structure, used especially as a material of high relative permittivity, includes a plurality of separate layers, each having a thickness of less than 500 Å, and based on hafnium dioxide (HfD₂), zirconium dioxide (ZrO₂) and alumina (Al₂O₃). In practice, the hafnium dioxide, zirconium dioxide and alumina layers form alloys of formula Hf_xZrAl_yO_z. Advantageously, the stoichiometry of the Hf_xZrAl_yO_z alloys varies from one layer to another.

Claims

1. A multilayer structure for use, as a material of high relative permittivity, comprising a plurality of separate layers, each having a thickness of less than 500 Å

, and at least one of which is based on hafnium dioxide (HfO₂), zirconium dioxide (ZrO₂) and alumina (Al₂O₃).

2. Multilayer structure according to claim 1, wherein the layers based on hafnium dioxide (HfO₂), zirconium dioxide (ZrO₂) and alumina (Al₂O₃) are formed from alloys of formula Hf_xZr_tAl_yO_z.

3. Multilayer structure according to claim 2, wherein stoichiometries of the alloys of formula Hf_xZr_tAl_yO_z vary from one layer to another.

4. Multilayer structure according to claim 1, wherein thickness of each layer is between 1 and 200 Å

.

5. Multilayer structure according to claim 1, wherein said plurality of separate layers comprises at least five layers.

6. Multilayer structure according to claim 1, wherein at least one external layer of said plurality of layers is made of alumina (Al₂O₃).

7. Multilayer structure according to claim 1, wherein each layer is deposited by technique of atomic layer deposition (ALD).

8. Multilayer structure according to claim 1, wherein the thickness of each layer is between 1 and 100 Å

.

9. Multilayer structure according to claim 1, wherein the thickness of each layer is between 1 and 50 Å

.