Q9Electrical Materials
Question
Q.9. Why silicon (Si) is preferred over Germanium (Ge) for semiconductors materials?
Answer
Silicon is preferred over germanium because of its larger band gap (1.1 eV vs 0.67 eV) giving lower leakage current and higher operating temperature, its stable native oxide (SiO₂) enabling planar fabrication, and its greater abundance/lower cost.
Silicon is preferred over germanium for semiconductor devices because: its larger band gap (≈1.1 eV versus ≈0.67 eV for Ge) gives a far smaller intrinsic carrier concentration at a given temperature, hence much lower reverse leakage current and stable operation up to higher temperatures (≈150-200°C for Si versus ≈70-85°C for Ge); silicon forms a stable, high-quality native oxide (SiO₂) which is the foundation of planar processing, MOS technology and surface passivation, whereas germanium's oxide is water-soluble and unstable; silicon has a higher breakdown field capability; and silicon is extremely abundant (from sand) and cheaper to process at scale than germanium.