| 摘要 |
The present invention relates to a heterojunction bipolar transistor structure having a device mesa 401 with a collector region 402, a base region 403 and an emitter region 404. An emitter metal layer 405 is connected to a ballast resistor 406 which in turn is connected to an emitter bump 407 by way of the air bridge 408. The thermal bump 409 is connected to the emitter metallization by way of a layer of heat dissipation material 410, preferably silicon nitride. The present structure enables dissipation of heat at the emitter contact as well as a ballast resistor connected to the emitter by way of metallization 405. This arrangement enables the dissipation of joule heat to avoid higher temperature of operation which results increased current at the collector which increases the temperature thereby further increasing the current, as well as provides a ballast resistor to reduce the collector current back to an acceptable value to avoid thermal runaway. The present invention effects the desired result without the creation of a natural resonator by separating the thermal and electrical paths.
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