A comparative device and performance analysis between a Si-Ge epitaxial-base HBT and a Si double-poly I/I BJT npn structure

The device characteristics and performance leverage of a SiGe epitaxial-base heterojunction bipolar transistor (HBT) are compared to those of an advanced Si double-poly ion-implanted (I/I)-base bipolar junction transistor (BJT) npn structure. In addition, a collector-base profile optimization for the SiGe device structure is described. Two-dimensional numerical process and device simulators and a lumped equivalent circuit model generator are used for the comparison along with experimental data. The simulated results show a greater than 3* increase in current gain, a 1.5* increase in the unity-gain cutoff frequency, and a 13% improvement in ECL circuit delay for the SiGe device. The experimental results confirm the device behavior predicted by the simulations.<
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