Topic: Semiconductor Devices
A sample of Si is doped with 10^17 donor atoms/cm³. Considering electron mobility in the doped Si 700 cm²/V-sec, the approximate resistivity of the doped Si is:
- A. 1 Ω-cm
- B. 10 Ω-cm
- C. 0.1 Ω-cm
- D. 100 Ω-cm
Answer: C. 0.1 Ω-cm
Explanation: N_d = 10^17 atoms/cm³, μ_e = 700 cm²/V-sec. Conductivity σ = N_d * q * μ_e = 10^17 * 1.6 * 10^-19 * 700 = 11.2 Ω^-1-cm^-1. Thus, resistivity ρ = 1 / σ ≈ 0.1 Ω-cm.