Patent US5801089A successfully refreshed from Google Patents.
US5801089A
Expired / Lapsed
US
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Method of forming stacked devices
Assignee: International Business Machines Corp
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Filing: 1995-06-07
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Granted: 1998-09-01
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Expires: 2015-06-07
Abstract
Abstract Chips having subsurface structures within or adjacent a horizontal trench in bulk single crystal semiconductor are presented. Structures include three terminal devices, such as FETs and bipolar transistors, rectifying contacts, such as pn diodes and Schottky diodes, capacitors, and contacts to and connectors between devices. FETs have low resistance connectors to diffusions while retaining low overlap capacitance. A low resistance and low capacitance contact to subsurface electrodes is achieved by using highly conductive subsurface connectors which may be isolated by low dielectric insulator. Stacks of devices are formed simultaneously within bulk single crystal semiconductor. A subsurface CMOS invertor is described. A process for forming a horizontal trench exclusively in heavily doped p+ regions is presented in which porous silicon is first formed in the p+ regions and then the porous silicon is etched.
Inventors
- 👤 Donald McAlpine Kenney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:04
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/67; H10D30/674; H10D30/6741; H10D30/6743; H10D30/6744; H10D30/6729; H10D30/673; H10D30/6733; H10D30/6737; H10D30/6739; H10D64/00; H10D64/20; H10D64/23; H10D64/231; H10D64/27; H10D64/281; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10D84/856; Y; Y10; Y10S; Y10S148/00; Y10S148/164
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
76 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer; and c) depositing conductive material a surface of said horizontal trench.
Claim 2
Independent Claim
76 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer; and c) depositing conductive material a surface of said horizontal trench.
Claim 3
Dependent Claim
21 words
A method as recited in claim 1, wherein said conductive material forms an ohmic contact with a terminal of a transistor.
Claim 4
Dependent Claim
24 words
A method as recited in claim 1, wherein said conductive material forms a rectifying contact with a portion of said bulk single crystal semiconductor.
Claim 5
Dependent Claim
18 words
A method as recited in claim 1, further comprising the step of depositing insulation on said conductive material.
Claim 6
Dependent Claim
16 words
A method as recited in claim 4, wherein said insulation does not fill said horizontal trench.
Claim 7
Dependent Claim
15 words
A method as recited in claim 5, wherein said insulation fills said first vertical trench.
Claim 8
Independent Claim
115 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer, said horizontal trench having a surface; and c) forming a layer of insulation on said surface of said horizontal trench; d) depositing conductive material on said layer of insulation; and e) forming a first and second heavily doped region within said bulk single crystal substrate adjacent said layer of insulation.
Claim 9
Independent Claim
115 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer, said horizontal trench having a surface; and c) forming a layer of insulation on said surface of said horizontal trench; d) depositing conductive material on said layer of insulation; and e) forming a first and second heavily doped region within said bulk single crystal substrate adjacent said layer of insulation.
Claim 10
Dependent Claim
29 words
A method as recited in claim 7, further comprising the steps of forming first and second conductive connectors in contact respectively with said first and second heavily doped regions.
Claim 11
Dependent Claim
40 words
A method as recited in claim 8, further comprising the step of forming a second vertical trench adjacent said first heavily doped region, wherein said connector forming step provides that said first conductive connector extends through said second vertical trench.
Claim 12
Dependent Claim
40 words
A method as recited in claim 8, further comprising the step of forming a second horizontal trench adjacent said first heavily doped region, wherein said connector forming step provides that said first conductive connector extends through said second horizontal trench.
Claim 13
Independent Claim
121 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer, said horizontal trench having a surface; and c) forming a layer of insulation on said surface of said horizontal trench; d) depositing conductive material on said layer of insulation; and e) forming a second vertical trench extending through said layer of conductive material, thereby forming electrically separated conductors on either side of said second vertical trench.
Claim 14
Independent Claim
121 words
A method of forming a buried connector in a substrate, the method comprising the steps of: a) forming a first vertical trench in bulk single crystal substrate; b) forming a horizontal trench buried within said bulk single crystal substrate starting from a portion of said first vertical trench, wherein said horizontal trench forming step is without the use of an adjacent substantially continuous p+ layer, said horizontal trench having a surface; and c) forming a layer of insulation on said surface of said horizontal trench; d) depositing conductive material on said layer of insulation; and e) forming a second vertical trench extending through said layer of conductive material, thereby forming electrically separated conductors on either side of said second vertical trench.
Claim 15
Dependent Claim
24 words
A method as recited in claim 11, wherein one said electrically separated conductors is not later contacted so as to form a floating gate.
Claim 16
Dependent Claim
29 words
A method as recited in claim 1, wherein said horizontal trench forming step is by one from the group, crystallographic etching, porous silicon etching, and dopant concentration preferential etching.
Claim 17
Independent Claim
101 words
A method of fabricating a semiconductor chip, comprising the steps of: a) providing a bulk single crystal substrate; b) forming a first horizontal trench buried within said bulk single crystal substrate, said first horizontal trench comprising a surface of bulk single crystal substrate, said trench adjacent a lightly doped region, a layer of a first material contacting said surface; and c) forming an electronic device having a first portion adjacent said first horizontal trench, said first portion being within said lightly doped region of said bulk single crystal substrate, said device further comprising a second portion within said first horizontal trench.
Claim 18
Independent Claim
101 words
A method of fabricating a semiconductor chip, comprising the steps of: a) providing a bulk single crystal substrate; b) forming a first horizontal trench buried within said bulk single crystal substrate, said first horizontal trench comprising a surface of bulk single crystal substrate, said trench adjacent a lightly doped region, a layer of a first material contacting said surface; and c) forming an electronic device having a first portion adjacent said first horizontal trench, said first portion being within said lightly doped region of said bulk single crystal substrate, said device further comprising a second portion within said first horizontal trench.
Claim 19
Dependent Claim
26 words
A method as recited in claim 14, wherein said layer of first material is a first electrically conductive material forming a contact with said first portion.
Claim 20
Dependent Claim
35 words
A method as recited in claim 14, wherein said first portion comprises a channel region of a transistor, said second portion comprises a gate region, and said layer of first material comprises a gate insulator.
Claim 21
Independent Claim
109 words
A method of fabricating a semiconductor chip, comprising the steps of: a) providing a bulk single crystal substrate; b) forming a first horizontal trench buried within said bulk single crystal substrate, said first horizontal trench comprising a surface of bulk single crystal substrate; c) forming an electronic device having a first portion adjacent said first horizontal trench, said fast portion being within said bulk single crystal substrate, said device further comprising a second portion within said first horizontal trench; d) forming a vertical trench intersecting said first portion; and e) forming a first electrically conducive material extending through said vertical trench and forming a contact with said first portion.
Claim 22
Independent Claim
109 words
A method of fabricating a semiconductor chip, comprising the steps of: a) providing a bulk single crystal substrate; b) forming a first horizontal trench buried within said bulk single crystal substrate, said first horizontal trench comprising a surface of bulk single crystal substrate; c) forming an electronic device having a first portion adjacent said first horizontal trench, said fast portion being within said bulk single crystal substrate, said device further comprising a second portion within said first horizontal trench; d) forming a vertical trench intersecting said first portion; and e) forming a first electrically conducive material extending through said vertical trench and forming a contact with said first portion.
References Cited (Backward Citations)
US4735821A
Cited
US5112771A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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