Semiconductors: Ge vs Si MCQ

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Ge vs SiHardQuestion 20214

Question

Silicon is preferred over germanium for semiconductor devices at high temperatures because:

A
Si has larger energy gap (1.1 eV vs 0.67 eV for Ge) so thermal carrier generation is smaller at high T
Correct
B
Si is cheaper
C
Ge has higher conductivity
D
Si operates at lower voltage

Correct answer

Si has larger energy gap (1.1 eV vs 0.67 eV for Ge) so thermal carrier generation is smaller at high T

Explanation

At high temperatures, thermally generated carriers overwhelm the doped carriers in Ge (Eg = 0.67 eV) first. Si (Eg = 1.1 eV) is stable to higher temperatures. Additionally, Si has higher melting point and lower leakage current.

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