GATE EC Electronic Devices questions

The bandgap of Silicon at room temperature is

A Silicon PN junction at a temperature of $20^{\circ} \mathrm{C}$ has a reverse saturation current of $10$ picoAmperes $(\mathrm{pA})$. The reverse saturation current at $40^{\circ} \mathrm{C}$ for the same bias is approximately

The primary reason for the widespread use of Silicon in semiconductor device technology is

A Silicon sample $\mathrm{A}$ is doped with $10^{18}$ atoms $/ \mathrm{cm}^{3}$ of Boron. Another sample $\mathrm{B}$ of identical dimensions is doped with $10^{18}$ atoms $/ \mathrm{cm}^{3}$ of Phosphorus. The ratio of electron to hole mobility is $3.$ The ratio of conductivity of the sample $\mathrm{A}$ to $\mathrm{B}$ is

A Silicon PN junction diode under reverse bias has depletion region of width $10 \; \mu \mathrm{m}$. The relative permittivity of Silicon,$\varepsilon_{r}=11.7$ and the permittiveity of free space $\varepsilon_{0}=8.85 \times 10^{-12} \mathrm{~F/m}$. The depletion capacitance of the diode per square meter is

In an abrupt $p-n$ junction, doping concentrations on $p$-side and $n$-side are $\mathrm{N}_{\mathrm{A}}=9 \times 10^{16} / \mathrm{cm}^{3}$ and $N_{0}=1 \times 10^{16} / \mathrm{cm}^{3}$ respectively. The $p-n$ junction is reverse biased and the total depletion width is $3 \; \mu \mathrm{m}$. The depletion width on the $p$-side is

The resistivity of a uniformloy doped $n$-type silicon sample is $0.5 \; \Omega-\mathrm{cm}$. If the electron mobility $\left(\mu_{n}\right)$ is $1250 \mathrm{~cm}^{2} / \mathrm{V}$-sec and the charge of an electron is $1.6 \times 10^{-19}$ Coulomb, the donor impurity concentration $\left(\mathrm{N}_{\text{n}}\right)$ in the sample is

Consider an abrupt $p$-junction. Let $V_{\text{in }}$ be the built-in potential of this junction and $\mathrm{V}_{\mathrm{R}}$ be the applied reverse bias. If the junction capacitance $\left(\mathrm{C}_{t}\right)$ is $1 \; \mathrm{pF}$ for $V_{\text{in}}+V_{\mathrm{R}}=1 \mathrm{~V}$, then for …

Consider the following statements $\mathrm{S} 1$ and $\mathrm{S} 2$. $\mathrm{S} 1 :$ The threshold voltage $\left(V_{T}\right)$ of a MOS capacitor decreases with increase in gate oxide thickness $\mathrm{S} 2 :$ The threshold voltage $\left(V_{t}\right)$ of a MOS capacitor decreases with increase in substrate doping concentration Which one of …

The longest wavelength that can be absorbed by silicon, which has the bandgap of $1.12 \; \mathrm{eV}$, is $1$. If the longest wavelength that can be absorbed by another material is $0.87 \; \mu \mathrm{m}$, then the bandgap of this material is

$n$-type silicon is obtained by doping silicon with

The bandgap of silicon at $300 \mathrm{~K}$ is

The intrinsic carrier concentration of silicon sample at $300 \mathrm{~K}$ is $1.5 \times 10^{16} / \mathrm{m}^3$. If after doping, the number of majority carriers is $5 \times 10^{20} / \mathrm{m}^3$, the minority carrier density is

Choose proper substitutes for $\mathrm{X}$ and $\mathrm{Y}$ to make the following statement correct Tunnel diode and Avalanche photodiode are operated in $\mathrm{X}$ bias and $\mathrm{Y}$ bias respectively.

An $n$-type silicon bar $0.1 \mathrm{~cm}$ long and $100 \; \mu \mathrm{m}^{2}$ in cross-sectional area has a majority carrier concentration of $5 \times 1020 / \mathrm{m}^{3}$ and the carrier mobility is $0.13 \mathrm{~m}^{0} / \mathrm{V}-s$ at $300 \mathrm{~K}$. If the charge of an electron is $1.6 \times 10^{-19}$ coulomb, then the …

The electron concentration in a sample of uniformly doped $n$-type silicon at $300 \mathrm{~K}$ varies linearly from $10^{17} / \mathrm{cm}^{3}$ at $x=0$ to $6 \times 10^{16} / \mathrm{cm}^{3}$ at $x=2 \; \mu \mathrm{m}$. Assume a situation that electrons are supplied to keep this concentration gradient constant with time. If electronic charge is …

Match items in Group $1$ with items in Group $2,$ most suitably. $$\begin{array}{ll} \textbf{Group 1} & \textbf{Group 2} \\ \text{P LED} & \text{1 Heavy doping} \\ \text{Q Avalanche photodiode} & \text{2 Coherent radiation} \\ \text{R Tunnel diode} & \text{3 Spontaneous emission} \\ \text{S LASER} & \text{Current gain} \end{array}$$

A particular green $\text{LED}$ emits light of wavelength $5490 \text{ A}$. The energy bandgap of the semiconductor material used there is (Planck's constant = $6.626 \times 10^{-34} \mathrm{~J-s})$

If $\mathrm{P}$ is Passivation, $\mathrm{Q}$ is $n$-well implant, $\mathrm{R}$ is metallization and $S$ is source/drain diffusion, then the order in which they are carried out in a standard $n$-well CMOS fabrication process, is

The action of a $\text{JFET}$ in its equivalent circuit can best be represented as a