US4937650A
Expired / Lapsed
US
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Semiconductor capacitor device with dual dielectric
Assignee: Hitachi Ltd
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Filing: 1988-09-21
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Granted: 1990-06-26
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Expires: 2008-09-21
Abstract
Abstract A semiconductor device having a large-capacitance capacitor in which an insulator film is formed underneath a film made of a material having a high dielectric constant, such as tantalum oxide, in such a manner that a portion of the insulator film underneath a defect region which is undesirably thin is thicker than other portions of the insulator film, thereby preventing occurrence of a failure in terms of dielectric strength and deterioration of the lifetime of the capacitor which would otherwise be caused by the existence of the defect region. Also disclosed is a process for producing such semiconductor device. Thus, it is possible to effectively prevent occurrence of problems which would otherwise be caused when a material having a high dielectric constant, such as tantalum oxide, is employed as a dielectric film of a capacitor, so that the reliability of a semiconductor having a large-capacitance capacitor is greatly improved.
Inventors
- 👤 Hiroshi Shinriki
- 👤 Yasushiro Nishioka
- 👤 Noriyuki Sakuma
- 👤 Kiichiro Mukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:51
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/83; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10D1/684; H10B; H10B12/00; H10B12/30; H10B12/31; H10D1/01; H10D1/041; H10D1/042; H10D1/62; H10D1/66; H10D1/692; H10D1/696; H10D64/00; H10D64/60; H10D64/62; H10D64/66; H10D64/68; H10D64/689; H10P; H10P95/00; H10P95/90; H10W; H10W20/00; H10W20/01; H10W20/031; Y; Y10; Y10S; Y10S257/00; Y10S257/915
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
167 words
A semiconductor device including a capacitor having a first electrode made of an electrically conductive substance, a first dielectric film formed on said first electrode, said first dielectric film having first and second regions, the first regions being relatively thin and the second regions being relatively thick as compared to the thickness of the first regions, a second electrode made of an electrically conductive substance and formed on said first dielectric film, and a second dielectric film formed between said first electrode and said first dielectric film, said second dielectric film being made of an oxide of said electrically conductive substance constituting said first electrode, and portions of said second dielectric film which are underneath said first regions of said first dielectric film being thicker than other portions of said second dielectric film, underneath said second regions of said first dielectric film, said other portions of said second dielectric film, underneath said second regions of said first dielectric film, having a thickness of at most 40 Å.
Claim 2
Dependent Claim
167 words
A semiconductor device including a capacitor having a first electrode made of an electrically conductive substance, a first dielectric film formed on said first electrode, said first dielectric film having first and second regions, the first regions being relatively thin and the second regions being relatively thick as compared to the thickness of the first regions, a second electrode made of an electrically conductive substance and formed on said first dielectric film, and a second dielectric film formed between said first electrode and said first dielectric film, said second dielectric film being made of an oxide of said electrically conductive substance constituting said first electrode, and portions of said second dielectric film which are underneath said first regions of said first dielectric film being thicker than other portions of said second dielectric film, underneath said second regions of said first dielectric film, said other portions of said second dielectric film, underneath said second regions of said first dielectric film, having a thickness of at most 40 Å.
Claim 3
Dependent Claim
46 words
A semiconductor device according to claim 1, wherein said first electrode is made of a substance selected from the group consisting of a single crystal silicon substrate, a polycrystalline silicon film, a silicide film, a titanium nitride film, an aluminum film and an aluminum-based alloy film.
Claim 4
Dependent Claim
26 words
A semiconductor device according to claim 2, wherein said silicide is selected from the group consisting of tungsten silicide, molybdenum silicide, titanium silicide and tantalum silicide.
Claim 5
Dependent Claim
34 words
A semiconductor device according to claim 1, wherein said first dielectric film is made of a material selected from the group consisting of tantalum oxide, titanium oxide, hafnium oxide, neodymium oxide and zirconium oxide.
Claim 6
Dependent Claim
40 words
A semiconductor device according to claim 1, wherein said second electrode is defined by a film made of a material selected from the group consisting of polycrystalline silicon, aluminum, aluminum-based alloy, tungsten, molybdenum, tungsten silicide, molybdenum silicide and titanium silicide.
Claim 7
Dependent Claim
19 words
A semiconductor device according to claim 1 which is a semiconductor memory having a MOS transistor and a capacitor.
Claim 8
Dependent Claim
75 words
A semiconductor device according to claim 6, wherein said semiconductor device includes a relatively thick insulator film for element isolation, wherein said MSO transistor includes a gate electrode, said gate electrode being spaced from said relatively thick insulator film, and wherein said capacitor is formed so as to extend laterally from an upper side of said gate electrode of said MOS transistor to an upper side of said relatively thick insulator film for element isolation.
Claim 9
Dependent Claim
21 words
A semiconductor device according to claim 1, wherein the first dielectric film is made of an oxide of a transition metal.
Claim 10
Dependent Claim
42 words
A semiconductor device according to claim 1, wherein the thickness of portions of said second dielectric film which are underneath said first regions of said first dielectric film is 40Å or more and is greater than the thickness of the other portions.
Claim 11
Dependent Claim
43 words
A semiconductor device according to claim 1, wherein the second dielectric film is a dielectric film formed by oxidation of the electrically conductive substance of the first electrode in a dry oxidizing atmosphere, after forming the first dielectric film on the first electrode.
Claim 12
Dependent Claim
22 words
A semiconductor device according to claim 10, wherein said dry oxidizing atmosphere is an atmosphere containing at most 1,000 ppm water vapor.
Claim 13
Dependent Claim
46 words
A semiconductor device according to claim 1, wherein the first electrode has a step portion and the first dielectric film is provided on the step portion, said first portions of said first dielectric film being provided at least on a side surface of said step portion.
Claim 14
Dependent Claim
26 words
A semiconductor device according to claim 1, wherein said first electrode is made of a substance selected from the group consisting of TiN, NbN and TaN.
Claim 15
Dependent Claim
17 words
A semiconductor device according to claim 1, wherein the first dielectric film is made of niobium oxide.
Claim 16
Dependent Claim
225 words
A semiconductor device including a capacitor having a first electrode made of an electrically conductive substance, a first dielectric film formed on said first electrode, said first dielectric film having first and second regions, the first regions being defect regions that are relatively thin and the second regions being relatively thick as compared to the thickness of the defect regions, a second electrode made of an electrically conductive substance and formed on said first dielectric film, and a second dielectric film formed between said first electrode and said first dielectric film, said second dielectric film being made of an oxide of said electrically conductive substance constituting said first electrode, and portions of said second dielectric film which are underneath said defect regions of said first dielectric film being thicker than other portions of said second dielectric film, underneath said second regions of said first dielectric film, said other portions of said second dielectric film, underneath said second regions of said first dielectric film, having a thickness of at most 40 angstroms, whereby the total thickness of the dielectric films at the defect regions is increased so that lowering of the dielectric strength due to the defect regions is avoided, while avoiding decreased capacitance by providing relatively thin other portions of the second dielectric film underneath the relatively thick second regions of the first dielectric film.
Claim 17
Dependent Claim
225 words
A semiconductor device including a capacitor having a first electrode made of an electrically conductive substance, a first dielectric film formed on said first electrode, said first dielectric film having first and second regions, the first regions being defect regions that are relatively thin and the second regions being relatively thick as compared to the thickness of the defect regions, a second electrode made of an electrically conductive substance and formed on said first dielectric film, and a second dielectric film formed between said first electrode and said first dielectric film, said second dielectric film being made of an oxide of said electrically conductive substance constituting said first electrode, and portions of said second dielectric film which are underneath said defect regions of said first dielectric film being thicker than other portions of said second dielectric film, underneath said second regions of said first dielectric film, said other portions of said second dielectric film, underneath said second regions of said first dielectric film, having a thickness of at most 40 angstroms, whereby the total thickness of the dielectric films at the defect regions is increased so that lowering of the dielectric strength due to the defect regions is avoided, while avoiding decreased capacitance by providing relatively thin other portions of the second dielectric film underneath the relatively thick second regions of the first dielectric film.
Claim 18
Dependent Claim
54 words
A semiconductor device according to claim 15, wherein said first electrode is made of a substance selected from the group consisting of a single crystal silicon substrate, a polycrystalline silicon film, a silicide film, a titanium nitride film, a niobium nitride film, a tantalum nitride film, an aluminum film and an aluminum-based alloy film.
Claim 19
Dependent Claim
36 words
A semiconductor device according to claim 16, wherein the first dielectric film is made of a material selected from the group consisting of tantalum oxide, titanium oxide, hafnium oxide, neodymium oxide, niobium oxide and zirconium oxide.
Claim 20
Dependent Claim
36 words
A semiconductor device according to claim 15, wherein the first dielectric film is made of a material selected from the group consisting of tantalum oxide, titanium oxide, hafnium oxide, neodymium oxide, niobium oxide and zirconium oxide.
References Cited (Backward Citations)
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