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US 5,329,156 AGranted
Feed bus for RF power transistors
AssigneeSpectrian Corporation
InventorHoward D. Bartlow
Life of this patent
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AssigneeSpectrian Corporation
InventorHoward D. Bartlow
Estimating the term…
The feeds to the emitter, base, and collector of an RF power transistor (source, drain, gate feeds of an RF FET) are configured so that negative mutual coupling therebetween is enhanced and positive mutual coupling therebetween is reduced. The emitter and base feeds include elongated portions which are generally parallel to each other with bonding pads provided on the elongated portions so that emitter and base currents flow in the same direction in the elongated portions and in the same direction as collector currents below. Interdigitated contact fingers extend from the elongated portions and contact the emitter region and the base region, respectively. When positive coupling of collector current and emitter current to the controlling base current is reduced or eliminated, the major thermal imbalance problem of operating RF transistors is also reduced or eliminated. Performance, linearity, efficiency, gain, and ruggedness are all enhanced in devices designed to utilize this invention.
An RF power transistor structure comprising a semiconductor body having a first (collector/drain) region and a second (emitter/source) region separated by a third (base/channel) region, a feed bus structure on one surface of said semiconductor body for feeding said second region and controlling said second region, said feed bus structure being configured so that third region current and second region current in said feed structure tend to flow parallel to each other and parallel to first region current and in the same direction to thereby enhance negative mutual coupling therebetween and reduce positive mutual coupling therebetween.
A bipolar RF power transistor structure comprising a semiconductor body having a collector region and an emitter region separated by a base region, a feed bus structure on one surface of said semiconductor body for feeding said emitter region and said base region, said feed bus structure being configured so that emitter current and base current in said feed structure tend to flow parallel to each other and parallel to collector current in said semiconductor body and in the same direction to thereby enhance negative mutual coupling therebetween and reduce positive mutual coupling therebetween.
A method of reducing hot spots in an RF bipolar power transistor having an emitter current, a base current, and an collector current during operation, said method comprising the step of configuring a feed bus structure to said emitter and said base whereby said emitter current, said base current, and said collector current tend to flow in parallel and in the same direction so that mutual magnetic coupling therebetween is negative.
A method of reducing hot spots in an RF field effect power transistor having a source current, a gate current, and a drain current during operation, said method comprising the step of configuring a feed bus structure to said source and said gate whereby said drain current, said gate current, and said source current tend to flow in parallel and in the same direction so that mutual magnetic coupling therebetween is negative.
Dependencies are inferred from the claim text.