EP0082331A2
Expired / Lapsed
EP
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Subsurface avalanche breakdown Zener diode
Assignee: International Business Machines Corp
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Filing: 1982-11-23
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Granted: —
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Expires: 2002-11-23
Abstract
Abstract This zener diode is fabricated by a conventional CMOS device fabricating process whereby an entire electronic circuit can be laid down in one overall process. A semiconductor substrate (10) of one conductivity type has an elongate region (12) of semiconductor material of the opposite conductivity type diffused to a predetermined depth to form a well, centrally of which a region (18) of enhanced conductivity material of the opposite conductivity type is diffused to a prearranged depth less than the predetermined depth. Semiconductor material of the one conductivity type is diffused into a pair of elongate regions (14, 16) spaced apart from, and with one on each side of, the first elongate region (12) while at the same time a quantity of the same material is diffused into the substrate between the pair of regions (14, 16) and over the central region (18) and doped more heavily than the substrate material to convert the upper part of the central region (18) and the well (12) to the opposite conductivity type for a substantial depth into the well whereby a P + N + junction is formed completely beneath the surface of the substrate. One contact (22) for the zener diode is made to the well region (12) outside the conductivity type converted part of the well. The other contact (24) is made to one (16) of the pair of regions (14.16).
Inventors
- 👤 Raymond Allen Muggli
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 13:13
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/20; H10D8/25
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
210 words
A subsurface avalanche breakdown zener diode formed in a semiconductor substrate (10) of one conductivity type material, comprising a first region (12) of the opposite conductivity type material formed from the outer surface (11) of said semiconductor substrate to a predetermined depth therein, a second region (18) of enhanced conductivity material of the opposite conductivity type formed centrally in said first region (12) from the outer surface of the substrate to a depth less than said predetermined depth, a pair of regions (14,16) of enhanced conductivity material of said one conductivity type disposed one on each side of said first region (12) extending down from the outer surface of the substrate and electrical contacts (22,24) made respectively to the first region (12) and one (16) of said pair of regions (14,16) and being characterised by said pair of regions (14,16) being spaced from said first region (12) and by a shallow third region (20) extending down from said outer surface of the same enhanced conductivity material as that of said pair of re q ions (14,16), the third region (20) interconnecting said pair of regions (14,16) and covering the second region (18) so that a buried PN junction is formed between the third region (20) and the second region (18).
Claim 2
Dependent Claim
210 words
A subsurface avalanche breakdown zener diode formed in a semiconductor substrate (10) of one conductivity type material, comprising a first region (12) of the opposite conductivity type material formed from the outer surface (11) of said semiconductor substrate to a predetermined depth therein, a second region (18) of enhanced conductivity material of the opposite conductivity type formed centrally in said first region (12) from the outer surface of the substrate to a depth less than said predetermined depth, a pair of regions (14,16) of enhanced conductivity material of said one conductivity type disposed one on each side of said first region (12) extending down from the outer surface of the substrate and electrical contacts (22,24) made respectively to the first region (12) and one (16) of said pair of regions (14,16) and being characterised by said pair of regions (14,16) being spaced from said first region (12) and by a shallow third region (20) extending down from said outer surface of the same enhanced conductivity material as that of said pair of re q ions (14,16), the third region (20) interconnecting said pair of regions (14,16) and covering the second region (18) so that a buried PN junction is formed between the third region (20) and the second region (18).
Claim 3
Dependent Claim
36 words
A zener diode as claimed in claim 1, in which the first region and said pair of regions are substantially rectangular, the length of the first region being greater than that of said pair of regions.
Claim 4
Dependent Claim
32 words
A zener diode as claimed in claim 1 or claim 2, in which the depth of said pair of regions is of the same order as the depth of the second region.
Claim 5
Dependent Claim
45 words
A zener diode as claimed in any preceding claim, in which said one conductivity type is N type, said opposite conductivity type is P type, the electrical contact to the first region is an anode contact, and the other electrical contact is a cathode contact.
Claim 6
Dependent Claim
18 words
A zener diode as claimed in any preceding claim formed in a complementary metal oxide semiconductor integrated circuit.
Claim 7
Dependent Claim
212 words
A subsurface avalanche breakdown zener diode formed in a complementary metal oxide semiconductor integrated circuit structure comprising, a semiconductor substrate (10) of one conductivity type and having an outer surface (11), a well (12) of semiconductor material of the opposite conductivity type extending from said outer surface (11) into said body to a predetermined depth, a first region (18) of enhanced conductivity material of said opposite conductivity type formed centrally in said well (12) to a prearranged depth from said outer surface (11) less than said predetermined depth, an electric contact (22) made at said outer surface (11) to said well (12) outside said first region (18), a pair of regions (14,16) of enhanced conductivity material of said one conductivity type arranged on either side of and spaced from said well (12) and extending into said body to a depth from said outer surface (11) of the order of said prearranged depth, a further region (20) of enhanced conductivity material of said one conductivity type bridging the gap between said pair of regions (14,16) over said first region (18), leaving said electric contact (22) uncovered, and contacting said first region (18) completely beneath said outer surface (11), and another electric contact (24) made to one (16) of said pair of regions (14,16).
Claim 8
Dependent Claim
212 words
A subsurface avalanche breakdown zener diode formed in a complementary metal oxide semiconductor integrated circuit structure comprising, a semiconductor substrate (10) of one conductivity type and having an outer surface (11), a well (12) of semiconductor material of the opposite conductivity type extending from said outer surface (11) into said body to a predetermined depth, a first region (18) of enhanced conductivity material of said opposite conductivity type formed centrally in said well (12) to a prearranged depth from said outer surface (11) less than said predetermined depth, an electric contact (22) made at said outer surface (11) to said well (12) outside said first region (18), a pair of regions (14,16) of enhanced conductivity material of said one conductivity type arranged on either side of and spaced from said well (12) and extending into said body to a depth from said outer surface (11) of the order of said prearranged depth, a further region (20) of enhanced conductivity material of said one conductivity type bridging the gap between said pair of regions (14,16) over said first region (18), leaving said electric contact (22) uncovered, and contacting said first region (18) completely beneath said outer surface (11), and another electric contact (24) made to one (16) of said pair of regions (14,16).
References Cited (Backward Citations)
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