GATE 2010 ECE Video Solutions on EDC (Electronic Devices and Circuits)

1. At room temperature, a possible value for the mobility of electrons in the inversion layer of a silicon N channel MOSFET is (in cm²/volt-sec)
a. 450
b. 1350
c. 1800
d. 3600

Answer: B

Solution : https://www.youtube.com/watch?v=bXxmszDCh1U


2. The gate oxide in a CMOS process is preferably grown using
a. Wet oxidation
b. Dry oxidation
c. Epitaxial deposition
d. Ion implantation

Answer: B

Solution : https://www.youtube.com/watch?v=7bi7sXWZYEc


3. In a uniformly doped BJT, assume that N_E, N_B and N_C are the emitter, base and collector doping in atoms/cm3 respectively. If the emitter injection efficiency of the BJT is close to unity, which of the following conditions is TRUE?
a. N_E = N_B = N_C
b. N_E >> N_B and N_B > N_C
c. N_E = N_B and N_B < N_C
d. N_E < N_B < N_C

Answer: B

Solution : https://www.youtube.com/watch?v=rGDV4GYPQaQ


4. Compared to a PN junction with N_D=N_A=10¹⁴ per cm³, which one of the following statements is TRUE for a PN junction with N_A=N_D=10²⁰ per cm³?
a. Reverse breakdown voltage is lower and depletion capacitance is lower
b. Reverse breakdown voltage is higher and depletion capacitance is lower
c. Reverse breakdown voltage is lower and depletion capacitance is higher
d. Reverse breakdown voltage is higher and depletion capacitance is higher

Answer: C

Solution : https://www.youtube.com/watch?v=wEzN6onF2AA


5. Linked Answer Question:
The silicon sample with unit cross sectional area shown below is in thermal equilibrium. The following information is given:
T = 300^oK
Electron charge = 1.6x10^-19 C
Thermal voltage = 26 mV
Electron mobility = 1350 cm²/volt-sec

i. The magnitude of the electric field at x = 0.5 µm is
a. 1 KV/cm
b. 5 KV/cm
c. 10 KV/cm
d. 26 KV/cm

Answer: C

ii. The magnitude of the electron drift current density at x = 0.5 µm is
a. 2.16x10⁴ A/cm²
b. 1.08x10⁴ A/cm²
c. 4.32x10³ A/cm²
d. 6.48x10² A/cm²

Answer: A

Solution : https://www.youtube.com/watch?v=jLAgBiAE4so