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GATE-2013 One Mark Questions & Solutions ( Electronic Devices)
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Specially designed for GATE EC Aspirants  Covers previous 10 years (2009-2018) 1 mark questions of Electronic Devices  Detailed solution provided  Related concept has been also explained

Akhilesh PANDEY
B.Tech. in EC, GATE 2017 AIR 18, YouTuber (channel name - STUDENT MODULATOR), 5 years Teaching Experience

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  1. Previous 10 Years (2009-18) 1 Mark Que.&Sol Subject: Electronic Devices Year: 2013 By- AKHILESH PANDEY


  2. About Me B. Tech. in Electronics & Communication GATE 2017 AIR 18 (EC) 5 Years Teaching Experience > Youtuber (channel- STUDENT MODULATOR)


  3. Q.1 In a forward biased PN junction diode, the sequence of events that best describesthe mechanism of current flow is (A) injection, and subsequent diffusion and recombination of minority carriers (B) injection, and subsequent drift and generation of minority carriers (C) extraction, and subsequent diffusion and generation of minority carriers (D) extraction, and subsequent drift and recombination of minority carriers


  4. Sol.1 When diode is forward biased: Due to injection of voltage, depletion width is lowered. The equilibrium initially established betweern forces tending to produce diffusion of majority carriers and the restraining influence of the potential energy barrier at junction is disturbed Hence, holes crosses from p-type to n-type and electrons crosses from n-type to p-type. Electrons in n-type recombines with injected minority carriers (holes) and holes in p-type recombines with injected minority carriers (electrons) Depletion Region Minority Carriers (electrons) Positive Donor lons Negative Acceptor lons Minority Carriers holes) Sequence of events: Injection, Diffusion, Recombination


  5. Q.2 In IC technology, dry oxidation (using dry oxygen) as compared to wet oxidation(using steam or water vapor) produces (A) superior quality oxide with a higher growth rate (B) inferior quality oxide with a higher growth rate (C) inferior quality oxide with a lower growth rate (D) superior quality oxide with a lower growth rate


  6. Sol.2 In CMOS fabrication process, oxidation can be done in two ways: Dry oxidation: Si + O2 SiO2 High quality oxide growth: uniform oxide film grown, good dielectric properties Slower oxidation process


  7. Wet oxidation: Si + 2H2O SiO2 + 2H2 Low quality oxide growth: non-uniform oxide film grown, dielectric properties are not good. >Faster oxidation process quality of gate oxide), so dry oxidation is preferred for gate oxide. For field oxide, dielectric properties are not so critical, so wet oxidation is use for it as the process is fast.


  8. Q.3 In a MOSFET operating in the saturation region, the channel length modulation effect causes (A) an increase in the gate-source capacitance (B) a decrease in the transconductance (C) a decrease in the unity-gain cutoff frequency (D) a decrease in the output resistance


  9. Sol.3 MOSFET is in saturation region, if DS GS Vcs GS Gate Metal Oxide Source Drain As the drain voltage increases, the voltage drop across the oxide near the drain terminal decreases, which means that the induced inversion charged density near the drain also decreases. Hence, channel length modulation occurs. n-type n-type p-type n-channel MOSFET


  10. Fractional change in the channel length is proportional to the drain bias, i.e. AVD where is the channel length modulation parameter. Since, the drain current is inversely proportional to electrical channel length,


  11. Thank You Rate Review Recommend Follow My Lectures on Unacademy akhilesh.pandey