US3619741A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of providing integrated diffused emitter ballast resistors for improved power capabilities of semiconductor devices
Assignee: Texas Instruments Inc
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Filing: 1969-11-24
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Granted: 1971-11-09
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Expires: 1989-11-24
Abstract
Abstract The disclosure is directed to planar transistors which include an emitter region disposed in a base region, the emitter region comprising an elongated spine from which spaced parallel emitter stripes project. The emitter electrode comprises a spine contact and individual electrode strips extending from the distal ends of the emitter fingers to locations spaced apart from the spine contact leaving discontinuities in the emitter electrode such that the sheet resistance of the emitter fingers underlying the discontinuities is utilized to form electrical ballast resistances in the emitter contact sufficient to prevent localized thermal runaway during operation of the transistor. The base contact has contact strips interdigitating with the emitter contact strips and extending from a common base electrode portion. Adjacent the discontinuities in the emitter contact, webs of emitter region material extend across the ends of the base contact strips and join adjacent ones of the emitter fingers to prevent deleterious localized current injection during operation of the transistor. An embodiment is also described in which the emitter region does not have a spine but consists of a series of spaced-apart, parallel extending fingers.
Inventors
- 👤 Lan Hambry Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:31
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10D; H10D99/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
162 words
A planar transistor including a base region of one conductivity type and an emitter region of opposite type inset in the base region, the emitter region comprising a common portion having spaced elongated portions projecting therefrom, a base electrode comprising electrode strips extending between said elongated emitter portions from a common base electrode portion, an emitter electrode system comprising an electrode portion on the said common emitter portion and electrode strips on the respective elongated emitter portions terminating short of the common emitter electrode portion whereby the sheet resistance of the elongated emitter portions not overlaid by said electrode strips provide series resistances between said common emitter electrode portions and said emitter electrode strips, and wherein webs of emitter material extend between and interconnect adjacent elongated emitter portions, the said webs being located between the ends of the base electrode strips and said common emitter portion in the vicinities of the ends of the emitter electrode strips adjacent the common emitter portion.
Claim 2
Dependent Claim
162 words
A planar transistor including a base region of one conductivity type and an emitter region of opposite type inset in the base region, the emitter region comprising a common portion having spaced elongated portions projecting therefrom, a base electrode comprising electrode strips extending between said elongated emitter portions from a common base electrode portion, an emitter electrode system comprising an electrode portion on the said common emitter portion and electrode strips on the respective elongated emitter portions terminating short of the common emitter electrode portion whereby the sheet resistance of the elongated emitter portions not overlaid by said electrode strips provide series resistances between said common emitter electrode portions and said emitter electrode strips, and wherein webs of emitter material extend between and interconnect adjacent elongated emitter portions, the said webs being located between the ends of the base electrode strips and said common emitter portion in the vicinities of the ends of the emitter electrode strips adjacent the common emitter portion.
Claim 3
Dependent Claim
23 words
The planar transistor of claim 1, wherein the emitter region comprises an elongated common spine portion and spaced parallel emitter stripes projecting therefrom.
Claim 4
Dependent Claim
188 words
A planar transistor including a base region of one conductivity type and discrete, spaced elongated emitter portions of opposite conductivity type inset in the base region, a base electrode having electrode strips extending between the said emitter portions from a common base contact portion, an emitter electrode system comprising a common portion ohmically connected to each of said emitter portions and emitter electrode strips overlying parts of the respective emitter portions and extending towards but spaced from the said common emitter electrode portion to leave an area of each emitter portion disposed between the electrode strip of that emitter portion and the common emitter electrode portion whereby the emitter electrode strips are effectively electrically connected to the said common emitter electrode portion by series resistances formed by the sheet resistance of the said areas of the emitter portions, and wherein webs of emitter material extend between and interconnect adjacent emitter portions, the said webs being located between the ends of the base electrode strips and the common emitter contact portion in the vicinities of the terminations of the emitter electrode strips at said areas of the emitter portions.
Claim 5
Dependent Claim
188 words
A planar transistor including a base region of one conductivity type and discrete, spaced elongated emitter portions of opposite conductivity type inset in the base region, a base electrode having electrode strips extending between the said emitter portions from a common base contact portion, an emitter electrode system comprising a common portion ohmically connected to each of said emitter portions and emitter electrode strips overlying parts of the respective emitter portions and extending towards but spaced from the said common emitter electrode portion to leave an area of each emitter portion disposed between the electrode strip of that emitter portion and the common emitter electrode portion whereby the emitter electrode strips are effectively electrically connected to the said common emitter electrode portion by series resistances formed by the sheet resistance of the said areas of the emitter portions, and wherein webs of emitter material extend between and interconnect adjacent emitter portions, the said webs being located between the ends of the base electrode strips and the common emitter contact portion in the vicinities of the terminations of the emitter electrode strips at said areas of the emitter portions.
Claim 6
Dependent Claim
53 words
The planar transistor of claim 3, wherein the emitter portions are parallel, spaced elongated portions ohmically interconnected at one end by a transversely extending common emitter electrode portion, wherein said emitter electrode strips extend from the opposite ends of said emitter portions to locations in the vicinity of said webs of emitter material.
Claim 7
Dependent Claim
174 words
A transistor device including emitter and base regions with a PN-junction therebetween, said emitter region including a common region from which individual spaced-apart portions project, said spaced-apart portions being disposed in the base region so that portions of the base region are interposed between said individual emitter portions; emitter electrode means ohmically connected to and distributed over said emitter regions, a portion of said electrode means being common to all said individual emitter portions, with discontinuities formed in said electrode means over areas of the said individual emitter portions to form electrical resistances sufficient to stabilize the current density of the device, thereby to prevent localized thermal runaway; and webs of material of said emitter region extending between and joining adjacent ones of said spaced emitter portions for screening said interposed portionS of said base region from electrical potential appearing on said common emitter portion, whereby localized current injection is reduced from parts of said emitter region adjacent said common portion of the emitter contact means into said interposed portions of said base region.
Claim 8
Dependent Claim
174 words
A transistor device including emitter and base regions with a PN-junction therebetween, said emitter region including a common region from which individual spaced-apart portions project, said spaced-apart portions being disposed in the base region so that portions of the base region are interposed between said individual emitter portions; emitter electrode means ohmically connected to and distributed over said emitter regions, a portion of said electrode means being common to all said individual emitter portions, with discontinuities formed in said electrode means over areas of the said individual emitter portions to form electrical resistances sufficient to stabilize the current density of the device, thereby to prevent localized thermal runaway; and webs of material of said emitter region extending between and joining adjacent ones of said spaced emitter portions for screening said interposed portionS of said base region from electrical potential appearing on said common emitter portion, whereby localized current injection is reduced from parts of said emitter region adjacent said common portion of the emitter contact means into said interposed portions of said base region.
Claim 9
Dependent Claim
26 words
The transistor device of claim 5, wherein said webs are disposed adjacent the junctures of said discontinuities and the electrode means overlying said individual emitter portions.
Claim 10
Dependent Claim
66 words
The transistor device of claim 5, wherein said common emitter portion is an elongated spine and said individual emitter portions are outwardly projecting stripes spaced along the length of said spine, said discontinuities being formed in the area of the juncture of said spine and said emitter stripes such that the sheet resistances of portions of said emitter stripes underlying the discontinuities form said electrical resistances.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |