US4761385A
Expired / Lapsed
US
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Forming a trench capacitor
Assignee: NXP USA Inc
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Filing: 1987-02-10
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Granted: 1988-08-02
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Expires: 2007-02-10
Abstract
Abstract A trench capacitor having increased capacitance. By means of the oxidation enhanced diffusion (OED) effect, locally outdiffused regions in the doped substrate of a semiconductor material may be formed. Thus, greater capacitance can be achieved for a trench capacitor of equal depth. This technique avoids the heretofore required extra doping in the well of opposite conductivity type that would have been necessary to prevent punchthrough if the entire lower, heavily doped region or substrate had to be formed closer to the surface of the overlying lightly doped semiconductor layer. The locally outdiffused regions may be accomplished by standard oxidation techniques.
Inventors
- 👤 James R. Pfiester
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:44
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/01; H10D1/045; H10D1/047; H10B; H10B12/00; H10B12/30; H10B12/37; H10D1/60; H10D1/62; H10D1/66; H10D1/665; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/92; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A process for forming a trench capacitor, comprising: providing a doped semiconductor substrate, relatively heavily doped with an impurity of a first conductivity type; providing a doped layer of semiconductor material on the semiconductor substrate, where the doped layer is relatively lightly doped with an impurity of the first conductivity type; providing a localized outdiffusion region extending from the doped semiconductor substrate into the doped layer of semiconductor material, where the localized outdiffused region is relatively heavily doped with the same impurity of the doped semiconductor substrate and the source of the impurity is the doped semiconductor substrate; providing a trench within the doped layer of semiconductor material extending into the localized outdiffusion region; providing a thin layer of dielectric material on the trench; and providing a region of conductive material on the layer of dielectric material in the trench.
Claim 2
Dependent Claim
140 words
A process for forming a trench capacitor, comprising: providing a doped semiconductor substrate, relatively heavily doped with an impurity of a first conductivity type; providing a doped layer of semiconductor material on the semiconductor substrate, where the doped layer is relatively lightly doped with an impurity of the first conductivity type; providing a localized outdiffusion region extending from the doped semiconductor substrate into the doped layer of semiconductor material, where the localized outdiffused region is relatively heavily doped with the same impurity of the doped semiconductor substrate and the source of the impurity is the doped semiconductor substrate; providing a trench within the doped layer of semiconductor material extending into the localized outdiffusion region; providing a thin layer of dielectric material on the trench; and providing a region of conductive material on the layer of dielectric material in the trench.
Claim 3
Dependent Claim
36 words
The process of claim 1 wherein the provision of the localized outdiffused region comprises growing an oxide region in an area of the substrate where the trench capacitor is formed, and subsequently removing the oxide region.
Claim 4
Dependent Claim
27 words
The process of claim 1 wherein the doped layer of semiconductor material is selected from the group of structures consisting of a well and an epitaxial layer.
Claim 5
Dependent Claim
171 words
A process for forming a trench capacitor, comprising: providing a doped semiconductor substrate, relatively heavily doped with an impurity of a first conductivity type; providing a doped layer of semiconductor material on the semiconductor substrate, where the doped layer is relatively lightly doped with an impurity of the first conductivity type and is selected from the group of structures consisting of a well and an epitaxial layer; growing an oxide region in an area of the substrate where the trench capacitor is to be formed and subsequently removing the oxide region to cause a localized outdiffusion region to diffuse from the doped semiconductor substrate into the doped layer of semiconductor material only in the proximity of the oxide region, where the localized outdiffused region is relatively heavily doped; providing a trench within the doped layer of semiconductor conductor material extending into the localized outdiffusion region; providing a thin layer of dielectric material on the trench; and providing a region of conductive material on the layer of dielectric material in the trench.
Claim 6
Dependent Claim
171 words
A process for forming a trench capacitor, comprising: providing a doped semiconductor substrate, relatively heavily doped with an impurity of a first conductivity type; providing a doped layer of semiconductor material on the semiconductor substrate, where the doped layer is relatively lightly doped with an impurity of the first conductivity type and is selected from the group of structures consisting of a well and an epitaxial layer; growing an oxide region in an area of the substrate where the trench capacitor is to be formed and subsequently removing the oxide region to cause a localized outdiffusion region to diffuse from the doped semiconductor substrate into the doped layer of semiconductor material only in the proximity of the oxide region, where the localized outdiffused region is relatively heavily doped; providing a trench within the doped layer of semiconductor conductor material extending into the localized outdiffusion region; providing a thin layer of dielectric material on the trench; and providing a region of conductive material on the layer of dielectric material in the trench.
References Cited (Backward Citations)
US204A
Cited
JPS6064444A
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JPS60140860A
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EP0149799A2
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JPS60154664A
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USH204H
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| 3.5 Years (Year 4) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
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