Patent EP0240273A2 successfully refreshed from Google Patents.
EP0240273A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Programmable transistors
Assignee: Exar Corp
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Filing: 1987-03-30
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Granted: —
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Expires: 2007-03-30
Abstract
Abstract An improved cell structure and method for making the same for semicustom chips which can be connected at the metalization step to form either an NPN or a PNP transistor and which has approximately the same cell size as a single PNP or NPN transistor. A central P-doped region (40) forms the emitter of the PNP transistor. This is partially surrounded by another P-doped region (42) which forms the collector of the PNP transistor. An N-doped region (46) is diffused into one of the P-doped regions (42) to form the emitter of an NPN transistor, with the selected P-doped region (42) becoming the base of the NPN transistor. In the gaps of the second P-doped region (42) surrounding the central P-doped region (40) is an N-doped region (44) which forms either the base of the PNP transistor or the collector of the NPN transistor.
Inventors
- 👤 Giovanni Piccolo Giannella
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 16:27
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/90; H10D84/901; H10D10/00; H10D10/40; H10D62/00; H10D62/10; H10D62/13; H10D62/133; H10D62/137
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
40 words
A semiconductor cell structure adaptable for forming either a bipolar PNP or NPN transistor, comprising: a first N-doped region; a first P-doped region; a second P-doped PNP region; and a second N-doped NPN region located within said second P-doped region.
Claim 2
Dependent Claim
40 words
A semiconductor cell structure adaptable for forming either a bipolar PNP or NPN transistor, comprising: a first N-doped region; a first P-doped region; a second P-doped PNP region; and a second N-doped NPN region located within said second P-doped region.
Claim 3
Dependent Claim
60 words
The cell structure of claim 1 further comprising: a first metal contact coupled to said first N-doped region as the collector of an NPN transistor; a second metal contact coupled to said second P-doped region as the base of an NPN transistor; and a third metal contact coupled to said second N-doped region as the emitter of said NPN transistor.
Claim 4
Dependent Claim
60 words
The cell structure of claim 1 further comprising: a first metal contact coupled to said first N-doped region as the base of a PNP transistor; a second metal contact coupled to said first P-doped region as the emitter of said PNP transistor; and a third metal contact coupled to said second P-doped region as the collector of said PNP transistor.
Claim 5
Dependent Claim
16 words
The cell structure of claim 1 wherein said regions are formed in an N- epitaxial layer.
Claim 6
Dependent Claim
38 words
The cell structure of claim 4 further comprising: a P-doped substrate beneath said epitaxial layer; and a P-doped isolation region surrounding said cell structure and extending between an outer surface of said epitaxial layer and said P-doped substrate.
Claim 7
Dependent Claim
33 words
The cell structure of claim 5 further comprising an N+ buried layer extending into said P-doped substrate in the area beneath said first and second N-doped regions and first and second P-doped regions.
Claim 8
Dependent Claim
23 words
The cell structure of claim 6 further comprising an N+ diffused area extending from said first N-doped region to said N+ buried layer.
Claim 9
Dependent Claim
31 words
The cell structure of claim 1 wherein said first P-doped region is located proximate to a center of said cell and said second P-doped region partially surrounds said first P-doped region.
Claim 10
Dependent Claim
22 words
The cell structure of claim 1 further comprising an oxide layer covering said regions and defining openings above each of said regions.
Claim 11
Dependent Claim
19 words
The cell structure of claim 1 further comprising a plurality of additional N-doped regions in said second P-doped region.
Claim 12
Dependent Claim
33 words
The cell structure of claim 10 further comprising an oxide layer covering said regions, said oxide layer having a plurality of openings to said second P-doped region between said N-doped NPN emitter regions.
Claim 13
Dependent Claim
28 words
The cell structure of claim 1 further comprising: a third P-doped PNP region; a third N-doped region located within said third P-doped region; and a fourth N-doped region.
Claim 14
Dependent Claim
47 words
The cell structure of claim 12 wherein said first P-doped region is located proximate the center of said cell and said second and third P-doped regions partially surround said first P-doped region, said first and fourth N-doped regions being located between said second and third P-doped regions.
Claim 15
Dependent Claim
22 words
The cell structure of claim 12 further comprising a plurality of N-doped regions in each of said second and third P-doped regions.
Claim 16
Dependent Claim
49 words
The cell structure of claim 14 further comprising an oxide layer covering said regions, said oxide layer having a plurality of openings to said N-doped regions within said P-doped regions and a plurality of openings to said second and third P-doped regions in between said N-doped NPN emitter regions.
Claim 17
Dependent Claim
28 words
The cell structure of claim 14 further comprising fourth, fifth, sixth and seventh P-doped regions, said fifth and seventh P-doped regions having a plurality of internal N-doped regions.
Claim 18
Independent Claim
71 words
A method for making a semiconductor cell structure on a wafer, said cell being adaptable for forming either a bipolar PNP or NPN transistor, comprising the steps of: diffusing a P-type dopant into said wafer to form a first P-doped region and a second P-doped region; and diffusing an N-type dopant into said wafer to form a first N-doped region and a second N-doped region located within said second P-doped region.
Claim 19
Independent Claim
71 words
A method for making a semiconductor cell structure on a wafer, said cell being adaptable for forming either a bipolar PNP or NPN transistor, comprising the steps of: diffusing a P-type dopant into said wafer to form a first P-doped region and a second P-doped region; and diffusing an N-type dopant into said wafer to form a first N-doped region and a second N-doped region located within said second P-doped region.
Claim 20
Dependent Claim
65 words
The method of claim 17 further comprising the steps of: forming a first metal contact coupled to said first N-doped region as the collector of an NPN transistor; forming a second metal contact coupled to said second P-doped region as the base of an NPN transistor; and forming a third metal contact coupled to said second N-doped region as the emitter of said NPN transistor.
Claim 21
Dependent Claim
65 words
The method of claim 17 further comprising the steps of: forming a first metal contact coupled to said first N-doped region as the base of a PNP transistor; forming a second metal contact coupled to said first P-doped region as the emitter of said PNP transistor; and forming a third metal contact coupled to said second P-doped region as the collector of said PNP transistor.
References Cited (Backward Citations)
No citation records indexed.
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