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Standard XII

Physics

Current Density Vector

An ideal MOS ...

Question

An ideal MOS capacitor has boron doping concentration of $10^{15} c m^{- 3}$ in the substrate. When a gate voltage is applied , a depletion region of width $0.5 μ m$ is formed with a surface (channel) potential of $0.2 V$ . Given that $ϵ_{0} = 8.854 \times 10^{- 14} F / c m$ and the relative permittivities of silicon and silicon dioxide are $12$ and $4$ , respectively,te peak electric field (in $V / μ m)$ in the oxide region is
2.4

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Solution

The correct option is A 2.4
Peak electric field in the oxide region is
$E_{o x} = \frac{ϵ_{s}}{ϵ_{o x}} E_{s}$
and $E_{s} = \frac{0.2 \times 2}{0.5}$
$E_{s} = 0.8 V / μ m$
$∴ E_{o x} = \frac{12}{4} \times 0.8$
$E_{o x} = 2.4 V / μ m$

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The correct option is A 2.4Peak electric field in the oxide region is Eox=ϵsϵoxEs and Es=0.2×20.5 Es=0.8 V/μm ∴Eox=124×0.8 Eox=2.4 V/μm

The correct option is A 2.4
Peak electric field in the oxide region is
$E_{o x} = \frac{ϵ_{s}}{ϵ_{o x}} E_{s}$
and $E_{s} = \frac{0.2 \times 2}{0.5}$
$E_{s} = 0.8 V / μ m$
$∴ E_{o x} = \frac{12}{4} \times 0.8$
$E_{o x} = 2.4 V / μ m$