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GATE 2014 EC (EC2) – Question 45

Electronic Devices · P-N Junction and Semiconductor Devices · 2 marks · Numerical answer

The abrupt PN junction shown is at 300 K. N-side depletion width $X_n=0.2$ µm and silicon permittivity $\epsilon_{si}=1.044\times10^{-12}$ F/cm. Find peak junction electric field (kV/cm).

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Correct answer: 30 to 32

Explanation

On the uniformly doped n-side, Poisson’s equation gives the triangular-field peak |Emax|=qNDXn/εsi. Use Xn=0.2µm=2×10⁻⁵cm, ND=10¹⁶cm⁻³ and εsi=1.044×10⁻¹²F/cm. The result is30651.34V/cm=**30.6513kV/cm**.