GATE ECE 2022 | Semiconductor Physics Question 14 | Electronic Devices and VLSI

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GATE ECE 2022

MCQ (More than One Correct Answer)

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Select the CORRECT statements regarding semiconductor devices

Electrons and holes are of equal density in an intrinsic semiconductor at equilibrium.

Collector region is generally more heavily doped than Base region in a BJT.

Total current is spatially constant in a two terminal electronic device in dark under steady state condition.

Mobility of electrons always increases with temperature in Silicon beyond 300 K.

GATE ECE 2021

MCQ (Single Correct Answer)

-0.67

A bar of silicon is doped with boron concentration of $10^{16} \mathrm{cm}^{-3}$ and assumed to be fully ionized. It is exposed to light such that electron-hole pairs are generated throughout the volume of the bar at the rate of $10^{20} \mathrm{~cm}^{-2} \mathrm{~s}^{-1}$. If the recombination lifetime is $100 \mu \mathrm{~s}$, intrinsic carrier concentration of silicon is $10^{10} \mathrm{~cm}^{-3}$ and assuming $100 \%$ ionization of boron, then the approximate product of steady-state electron and hole concentrations due to this light exposure is

$10^{20} \mathrm{~cm}^{-6}$

$2 \times 10^{32} \mathrm{~cm}^{-6}$

$10^{32} \mathrm{~cm}^{-6}$

$2 \times 10^{20} \mathrm{~cm}^{-6}$

GATE ECE 2021

MCQ (Single Correct Answer)

-0.67

The energy band diagram of a $p$-type semiconductor bar of length $L$ under equilibrium condition (i.e., the Fermi energy level $E_F$ is constant) is shown in the figure. The valance band $E_V$ is sloped since doping is non-uniform along the bar. The different between the energy levels of the valence band at the two edges of the bar is $\Delta$.

GATE ECE 2021 Electronic Devices and VLSI - Semiconductor Physics Question 3 English If the charge of an electron is $q$, then the magnitude of the electric field developed inside the semiconductor bar is

$\frac{2 \Delta}{q L}$

$\frac{\Delta}{2 q L}$

$\frac{\Delta}{q L}$

$\frac{3 \Delta}{2 q L}$

GATE ECE 2017 Set 1

Numerical

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The dependence of drift velocity of electrons on electric field in a semiconductor is shown below. The semiconductor has a uniform electron concentration of n = 1x10¹⁶ $$cm^{-3}$$ and electronic charge q = 1.6x10^-19 C. If a bias of 5V is applied across a 1 $$\mu$$m region of this semiconductor, the resulting current density in this region, in kA/cm², is _________. GATE ECE 2017 Set 1 Electronic Devices and VLSI - Semiconductor Physics Question 21 English