Patent US6514828B2 successfully refreshed from Google Patents.
US6514828B2
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Method of fabricating a highly reliable gate oxide
Assignee: Micron Technology Inc
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Filing: 2001-04-20
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Granted: 2003-02-04
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Expires: 2021-04-20
Abstract
Abstract An ultra-thin gate oxide layer of hafnium oxide (HfO 2 ) and a method of formation are disclosed. The ultra-thin gate oxide layer of hafnium oxide (HfO 2 ) is formed by a two-step process. A thin hafnium (Hf) film is first formed by thermal evaporation at a low substrate temperature, after which the thin hafnium film is radically oxidized using a krypton/oxygen (Kr/O 2 ) high-density plasma to form the ultra-thin gate oxide layer of hafnium oxide (HfO 2 ). The ultra-thin gate oxide layer of hafnium oxide (HfO 2 ) formed by the method of the present invention is thermally stable in contact with silicon and is resistive to impurity diffusion at the HfO 2 /silicon interface. The formation of the ultra-thin gate oxide layer of hafnium oxide (HfO 2 ) eliminates the need for a diffusion barrier layer, allows thickness uniformity of the field oxide on the isolation regions and, more importantly, preserves the atomically smooth surface of the silicon substrate.
Inventors
- 👤 Kie Y. Ahn
- 👤 Leonard Forbes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:52
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/68; H10D64/691; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01346; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; H10P14/6319; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69392
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
61 words
A method for forming a gate structure for a semiconductor device comprising the steps of: forming a hafnium layer on a semiconductor substrate by thermal evaporation at a temperature of about 150° C. to about 200° C.; converting said hafnium layer to a hafnium oxide layer by oxidizing said hafnium layer; and forming a conductive layer over said hafnium oxide layer.
Claim 2
Independent Claim
61 words
A method for forming a gate structure for a semiconductor device comprising the steps of: forming a hafnium layer on a semiconductor substrate by thermal evaporation at a temperature of about 150° C. to about 200° C.; converting said hafnium layer to a hafnium oxide layer by oxidizing said hafnium layer; and forming a conductive layer over said hafnium oxide layer.
Claim 3
Dependent Claim
23 words
The method of claim 1 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 100 Angstroms.
Claim 4
Dependent Claim
23 words
The method of claim 2 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 50 Angstroms.
Claim 5
Dependent Claim
21 words
The method of claim 1 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with atomic oxygen.
Claim 6
Dependent Claim
23 words
The method of claim 4 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density krypton plasma.
Claim 7
Dependent Claim
27 words
The method of claim 5 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density krypton plasma at about 400° C.
Claim 8
Dependent Claim
28 words
The method of claim 6 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C.
Claim 9
Dependent Claim
33 words
The method of claim 7 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a 3% high-density oxygen/krypton plasma at about 400° C. and at about 1 Torr.
Claim 10
Dependent Claim
28 words
The method of claim 1 , wherein said conductive layer is formed of a material selected from the group consisting of metals, metal silicides, polysilicon and metal oxides.
Claim 11
Dependent Claim
14 words
The method of claim 1 , wherein said semiconductor substrate is a silicon substrate.
Claim 12
Dependent Claim
27 words
The method of claim 10 , wherein said silicon substrate has a surface of < 100 > orientation, said surface being adjacent to said hafnium oxide layer.
Claim 13
Dependent Claim
27 words
The method of claim 10 , wherein said silicon substrate has a surface of < 111 > orientation, said surface being adjacent to said hafnium oxide layer.
Claim 14
Dependent Claim
15 words
The method of claim 1 further comprising forming a silicide layer overlying said conductive layer.
Claim 15
Dependent Claim
15 words
The method of claim 13 further comprising forming a cap layer overlying said silicide layer.
Claim 16
Independent Claim
100 words
A method of forming a memory cell comprising the steps of: forming at least one gate stack over a substrate, said gate stack comprising a hafnium oxide layer of about 10 Angstroms to about 100 Angstroms thick and a conductive layer over and in contact with said hafnium oxide layer, wherein said hafnium oxide layer is formed by oxidizing a hafnium layer with a high-density krypton plasma; forming source and drain regions in said substrate on opposite sides of each of said plurality of gate stacks; and forming a storage device connected to one of said source and drain regions.
Claim 17
Independent Claim
100 words
A method of forming a memory cell comprising the steps of: forming at least one gate stack over a substrate, said gate stack comprising a hafnium oxide layer of about 10 Angstroms to about 100 Angstroms thick and a conductive layer over and in contact with said hafnium oxide layer, wherein said hafnium oxide layer is formed by oxidizing a hafnium layer with a high-density krypton plasma; forming source and drain regions in said substrate on opposite sides of each of said plurality of gate stacks; and forming a storage device connected to one of said source and drain regions.
Claim 18
Dependent Claim
15 words
The method of claim 15 , wherein said hafnium layer is formed by thermal evaporation.
Claim 19
Dependent Claim
16 words
The method of claim 16 , wherein said hafnium layer is formed by electron beam evaporation.
Claim 20
Dependent Claim
23 words
The method of claim 17 , wherein said hafnium layer is formed at a temperature of about 150° C. to about 200° C.
Claim 21
Dependent Claim
23 words
The method of claim 18 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 100 Angstroms.
Claim 22
Dependent Claim
23 words
The method of claim 19 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 50 Angstroms.
Claim 23
Dependent Claim
27 words
The method of claim 15 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density krypton plasma at about 400° C.
Claim 24
Dependent Claim
28 words
The method of claim 21 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C.
Claim 25
Dependent Claim
33 words
The method of claim 22 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a 3% high-density oxygen/krypton plasma at about 400° C. and at about 1 Torr.
Claim 26
Dependent Claim
28 words
The method of claim 15 , wherein said conductive layer is formed of a material selected from the group consisting of metals, metal silicides, polysilicon and metal oxides.
Claim 27
Dependent Claim
13 words
The method of claim 15 , wherein said substrate is a semiconductor substrate.
Claim 28
Dependent Claim
14 words
The method of claim 25 , wherein said semiconductor substrate is a silicon substrate.
Claim 29
Dependent Claim
27 words
The method of claim 26 , wherein said silicon substrate has a surface of < 100 > orientation, said surface being adjacent to said hafnium oxide layer.
Claim 30
Dependent Claim
27 words
The method of claim 26 , wherein said silicon substrate has a surface of < 111 > orientation, said surface being adjacent to said hafnium oxide layer.
Claim 31
Independent Claim
54 words
A method of providing an oxide layer over of a surface of a silicon substrate comprising the steps of: thermally evaporating a hafnium layer over said surface at a temperature of about 150° C. to about 200° C.; and oxidizing said hafnium layer with a high-density krypton plasma to form a hafnium oxide layer.
Claim 32
Independent Claim
54 words
A method of providing an oxide layer over of a surface of a silicon substrate comprising the steps of: thermally evaporating a hafnium layer over said surface at a temperature of about 150° C. to about 200° C.; and oxidizing said hafnium layer with a high-density krypton plasma to form a hafnium oxide layer.
Claim 33
Dependent Claim
16 words
The method of claim 29 , wherein said hafnium layer is formed by electron beam evaporation.
Claim 34
Dependent Claim
23 words
The method of claim 29 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 100 Angstroms.
Claim 35
Dependent Claim
23 words
The method of claim 31 , wherein said hafnium layer is formed to a thickness of about 10 Angstroms to about 50 Angstroms.
Claim 36
Dependent Claim
27 words
The method of claim 29 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density krypton plasma at about 400° C.
Claim 37
Dependent Claim
28 words
The method of claim 33 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C.
Claim 38
Dependent Claim
33 words
The method of claim 34 , wherein said hafnium oxide layer is formed by oxidizing said hafnium layer with a 3% high-density oxygen/krypton plasma at about 400° C. and at about 1 Torr.
Claim 39
Dependent Claim
14 words
The method of claim 29 , wherein said surface has < 100 > orientation.
Claim 40
Dependent Claim
14 words
The method of claim 29 , wherein said surface has < 111 > orientation.
Claim 41
Independent Claim
73 words
A method of forming a gate structure for a semiconductor device comprising the steps of: thermally evaporating a hafnium layer over a surface of a silicon substrate at a temperature of about 150° C. to about 200° C.; oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C. and at about 1 Torr to form a hafnium oxide layer; and forming a conductive layer over said hafnium oxide layer.
Claim 42
Independent Claim
73 words
A method of forming a gate structure for a semiconductor device comprising the steps of: thermally evaporating a hafnium layer over a surface of a silicon substrate at a temperature of about 150° C. to about 200° C.; oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C. and at about 1 Torr to form a hafnium oxide layer; and forming a conductive layer over said hafnium oxide layer.
Claim 43
Independent Claim
72 words
A method of providing a hafnium oxide layer having a thickness of about 10 Angstroms over of a surface of a silicon substrate comprising the steps of: thermally evaporating a hafnium layer over said surface at a temperature of about 150° C. to about 200° C.; and oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C. and at about 1 Torr to form said hafnium oxide layer.
Claim 44
Independent Claim
72 words
A method of providing a hafnium oxide layer having a thickness of about 10 Angstroms over of a surface of a silicon substrate comprising the steps of: thermally evaporating a hafnium layer over said surface at a temperature of about 150° C. to about 200° C.; and oxidizing said hafnium layer with a high-density 3% oxygen/krypton plasma at about 400° C. and at about 1 Torr to form said hafnium oxide layer.
References Cited (Backward Citations)
US6087243A
Cited
US6153538A
Cited
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