SiGe
Understanding SiGe
SiGe bridges the gap between low-cost silicon CMOS and high-performance III-V technologies (GaAs, InP). By adding germanium to the silicon base, the HBT achieves much higher frequency operation than silicon BJT while maintaining compatibility with standard silicon fab processes.
SiGe vs Other Technologies
| Parameter | SiGe HBT | GaAs pHEMT | Si CMOS |
|---|---|---|---|
| fT | 200-500 GHz | 100-200 GHz | 200-400 GHz |
| NF (10 GHz) | 0.5-1 dB | 0.3-0.5 dB | 1-2 dB |
| 1/f corner | 1-100 kHz | 1-10 MHz | 100 kHz-10 MHz |
| Cost | $ | $ | |
| Integration | High | Moderate | Very high |
Frequently Asked Questions
What is SiGe?
SiGe (Silicon Germanium) is a semiconductor technology using heterojunction bipolar transistors with germanium in the base. It achieves high-frequency performance (fT > 300 GHz) at lower cost than GaAs by using silicon fabrication infrastructure.
What is SiGe used for?
Low-phase-noise VCOs and synthesizers (best 1/f noise), receiver ICs (77 GHz automotive radar, 5G), transceiver SoCs, high-speed ADCs and DACs, and mmWave imaging. SiGe dominates automotive radar at 77 GHz.
What is the advantage of SiGe over CMOS?
SiGe HBTs have better noise performance, higher breakdown voltage, better analog linearity, and much lower flicker noise than CMOS transistors. SiGe is preferred for analog/RF functions that require the best performance.