In semiconductor device terminology, the phrase “enhancement mode” is most closely associated with which electronic component?
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Atunnel diode
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BMOSFET
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CJFET
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Dphoto diode
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Ethyristor
Answer
Correct Answer: MOSFET
Explanation
Introduction / Context:“Enhancement mode” is a mode of operation where a device is normally off at zero gate bias and requires an applied voltage to turn on. The term is a hallmark of MOSFET operation, differentiating it from depletion-mode devices.
Given Data / Assumptions:
- Enhancement mode implies gate voltage enhances channel conduction.
- Depletion mode implies gate voltage depletes a pre-existing channel.
Concept / Approach:MOSFETs are manufactured as either enhancement-type or depletion-type. Enhancement MOSFETs conduct only when sufficient gate–source voltage exceeds threshold, making them normally off at VGS = 0. JFETs are depletion-mode devices, normally on at VGS = 0 and pinched off with reverse gate bias. Tunnel diodes and photodiodes do not use this terminology.
Step-by-Step Solution:
Identify enhancement vs depletion definition.Check device families: MOSFET supports both; JFET only depletion.Therefore, correct association is MOSFET.Verification / Alternative check:
Datasheets for logic MOSFETs always state “enhancement-mode MOSFET” if it requires positive VGS to turn on (nMOS example).Why Other Options Are Wrong:
Tunnel diode: characterized by negative resistance, not enhancement.JFET: depletion type, normally on.Photodiode: operates via light excitation, no enhancement/depletion terminology.Thyristor: controlled by gate triggering, not described as enhancement-mode.Final Answer:
MOSFET