Rf Micro Devices, Inc.

Larry W Kapitan

Arthur E Geiss

Wayne Lewis

Matthew L Seaford

Thomas J Rogers

Michael T Fresina

Curtis A Barratt

Ramond Jeffrey Vass

Arthur E Geissberger

The present invention provides a highly doped semiconductor layer. More specifically, the present invention provides a semiconductor layer that includes at least two impurities. Each impurity is introduced at a level below its respective degradation concentration. In this manner, the two or more impurities provide an additive conductivity to the semiconductor layer at a level above the conductivity possible with any one of the impurities alone, due to the detrimental effects that would be created by increasing the concentration of any one impurity beyond its degradation concentration.

Semiconductor layer

Highly conductive semiconductor layer having two or more impurities

A voltage variable resistor formed on heterojunction bipolar transistor epitaxial material includes a current channel made on emitter material. Emitter mesas separated by a recess provide the contacts for the voltage variable resistor. Each mesa is topped with emitter metal forming the resistor contacts. The emitter mesas are layered on top of the current channel that is layered atop of a base layer. The voltage variable resistor's control contact is provided by a base contact located on the base layer and separated from the current channel.

Voltage variable resistor from HBT epitaxial layers

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Hampton, NJ, United States of America

Larry W Kapitan