GATE EC||ELECTRONIC DEVICES AND CIRCUIT||DEVICE TECHNOLOGY||PYQS(2000-2025)

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Question 1

The primary advantage of ion implantation over thermal diffusion is:

(GATE 2004 || EC || MCQ || 1 MARK)

  • Lower fabrication cost

  • precise control over the dopant profile

  • No annealing required

  • Higher oxide growth rate

Question 2

Match items in Group-1 with items in Group-2, most suitably.

Group-1

P. LED

Q. Avalanche

R. Tunnel diode

S. LASER

Group-2

1. Heavy doping

2.Coherent radiation 

3.Spontaneous emission

4. Current gain

(GATE 2003 || EC || MCQ ||1 MARK)

  • P - 1; Q – 2; R – 4; S–3

  •  P – 2; Q –3; R – 1; S–4

  • P – 3; Q – 4; R –1; S–2

  •  P – 2; Q – 1; R – 4; S–3

Question 3

Photolithography in VLSI fabrication is mainly used for:

(GATE 2005 || EC || MCQ || 1 MARK)

  • Doping silicon wafer

  • Growing oxide layer

  • Metal deposition

  • Pattern transfer onto wafer

Question 4

The major limitation in conventional optical lithography arises due to:

(GATE 2013 || EC || MCQ ||1 MARK)

  • Electron scattering

  • Diffusion current

  • Diffraction effects

  • Thermal runaway

Question 5

Hot carrier effect in short-channel MOSFETs is caused by:

(GATE 2017 || EC || MCQ ||1 MARK)

  • High electric field near drain

  • Thick oxide layer

  • Low substrate doping

  • Low electric field

Question 6

In modern CMOS technology, high-k dielectrics are used mainly to:


(GATE 2024 || EC || NAT ||1 MARK)

  • Increase leakage current

  • Reduce gate leakage current

  • Reduce carrier mobility

  • Increase channel length

Question 7

A Zener diode, when used in voltage stabilization circuits, is biased in  


(GATE 2011 || EC || MCQ ||1 MARK)

  • reverse bias region below the breakdown voltage

  • reverse breakdown region.

  • forward bias region

  • forward bias constant current mode

Question 8

 A pn junction solar cell of area 1.0 cm2, illuminated uniformly with 100mW cm-2, has the following parameters:

Efficiency = 15%, open circuit voltage = 0.7 V, fill factor = 0.8, and thickness = 200 um. The charge of an electron 1.6 × 10-19 C. The average optical generation rate (in cm-3s-1) is


(GATE 2020 || EC || MCQ ||1 MARK)

  •  1.04 × 1019

  • 0.84 × 1019

  • 5.57 × 1019

  • 83.60 × 1019

Question 9

A solar cell of area 1.0 cm2, operating at 1.0 sun intensity, has a short circuit current of 20 mA, and an open circuit voltage of 0.65 V. Assuming room temperature operation and thermal equivalent voltage of 26 mV, the open circuit voltage (in volts, correct to two decimal places) at 0.2 sun intensity is ___.


(GATE 2018 || EC || NAT ||1 MARK)

  • 0.59 to 0.63

Question 10

Red (R), Green (G) and Blue (B) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different band-gaps. The built-in voltages of red, green and blue diodes are VR, VG and VB, respectively. Assume donor and acceptor doping to be the same (NA and ND) respectively in the p and n sides of all the three diodes.

Which one of the following relationship about the built-in voltages is TRUE?


(GATE 2018 || EC || MCQ ||1 MARK)

  • VR > VG > VB


  • VR < VG < VB


  •  VR = VG = VB


  •  VR > VG < VB

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