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EP0035841A2
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A shorted-emitter thyristor device
Assignee: Siemens Mobility Ltd
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Filing: 1981-02-24
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Granted: —
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Expires: 2001-02-24
Abstract
Abstract In a thyristor device (1) the dynamic characteristics, e.g. critical dV / dt, of the thyristor may be improved by means of shorts (2) between the base layer (4) and the emitter metallisation layer (9). Such shorts, however, slow the rate of conduction spreading. To overcome this the series resistance (Rs) of the shorts (2) is made at least equal to the maximum effective lateral resistance (Ra) of the base layer between the shorts (2) by means of a layer (7) of resistive material provided between the upper surface of the columns (3) of the shorts (2) and the emitter metallisation layer (9). The resistive material may be silicon of the same type as the base layer (4) but possessing higher resistivity or a cermetfilm. In another form in the upper surface of the columns (3) of the shorts (2), in contact with metallisation layer (9), a moat (13) surrounding a central land (12) is etched to leave only a relatively small contact area.
Inventors
- 👤 Patrick Laurence Thomas Bishop
- 👤 John Mansell Garrett
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 16:37
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/141; H10D62/148; H10D64/00; H10D64/20; H10D64/23; H10D64/233; H10D84/00; H10D84/101; H10D84/131; H10D84/133
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
117 words
A shorted-emitter thyristor device (1) comprising a plurality of superimposed semiconductor layers of alternating conductivity type including an emitter end layer (6) and an adjacent base layer (4), the emitter layer (6) having formed therein a plurality of perforations (5) through each of which extends a column (3) of base layer (4) material to make ohmic contact with a metallisation layer (9) on the end surface of the emitter layer (6) constituting a short (2) between the base layer (4) and the emitter metallisation layer (9) characterised in that the series resistance (Rs) of the short (2) is at lease equal to the maximum effective lateral resistance (Ra) of the base layer (4) between said shorts (2).
Claim 2
Dependent Claim
117 words
A shorted-emitter thyristor device (1) comprising a plurality of superimposed semiconductor layers of alternating conductivity type including an emitter end layer (6) and an adjacent base layer (4), the emitter layer (6) having formed therein a plurality of perforations (5) through each of which extends a column (3) of base layer (4) material to make ohmic contact with a metallisation layer (9) on the end surface of the emitter layer (6) constituting a short (2) between the base layer (4) and the emitter metallisation layer (9) characterised in that the series resistance (Rs) of the short (2) is at lease equal to the maximum effective lateral resistance (Ra) of the base layer (4) between said shorts (2).
Claim 3
Dependent Claim
27 words
A thyristor device according to Claim 1 wherein the short (2) makes ohmic contact with the metallisation layer (9) through a further layer of resistive material (7).
Claim 4
Dependent Claim
29 words
A thyristor device according to Claim 2 wherein the resistive material (7) comprises silicon of the same type as the base region (4) and of a relatively higher resistivity.
Claim 5
Dependent Claim
27 words
A thyristor device according to Claim 2 wherein the resistive material (7) comprises a cermet film of silicon dioxide or the like doped with a metallic conductor.
Claim 6
Dependent Claim
51 words
A thyristor device according to Claim 2 wherein the layer of resistive material (7) comprises a layer of metal sintered into the end surface of the emitter layer (6) including the shorts (2) and the metallisation layer (9) is absent from a region overlaying a short (2) and its immediate vicinity.
Claim 7
Dependent Claim
24 words
A thyristor device according to any of Claims 2,3 or 4 or 5 wherein the resistive material (7) possesses a negative coefficient of resistivity.
Claim 8
Dependent Claim
30 words
A thyristor device according to any of Claims 2 to 6 wherein the layer of resistive material (7) is deposited in rectilinear strips to intersect a plurality of shorts (2).
Claim 9
Dependent Claim
35 words
A thyristor device according to any of Claims 2 to 7 wherein the layer of resistive material (7) comprises a composite layer of a first preferred ohmic contact material and a second preferred resistive material.
Claim 10
Dependent Claim
36 words
A thyristor device according to Claim 1 wherein the column (3) of material comprising a short (2) has a region (12) of reduced lateral cross-section whereby substantially to determine the series resistance of the short (2).
Claim 11
Dependent Claim
26 words
1 0 . A thyristor device according to Claim 9 wherein the region (12) of reduced cross-section is in ohmic contact with the metallisation layer (9).
Claim 12
Dependent Claim
33 words
A thyristor device according to Claim 10 wherein said region (12) of reduced cross-section comprises a land (12) in ohmic contact with the metallisation layer and surrounded by a relatively lowered region (13).
References Cited (Backward Citations)
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