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    13-MOSFET - Design and Analysis-24!02!2024

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    ashbinny1
    The document discusses transistors and MOSFETs. It describes the device structures and operating principles of bipolar junction transistors (BJT) and metal-oxide-semiconductor field-effect transistors (MOSFET). It discusses MOSFET configurations like common source, common drain, and common gate. It also discusses enhancement mode and depletion mode MOSFETs, and how complementary MOSFETs use both n-channel and p-channel types.

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    13-MOSFET - Design and Analysis-24!02!2024

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    ashbinny1
    11 views14 pages
    The document discusses transistors and MOSFETs. It describes the device structures and operating principles of bipolar junction transistors (BJT) and metal-oxide-semiconductor field-effect transistors (MOSFET). It discusses MOSFET configurations like common source, common drain, and common gate. It also discusses enhancement mode and depletion mode MOSFETs, and how complementary MOSFETs use both n-channel and p-channel types.

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    The document discusses transistors and MOSFETs. It describes the device structures and operating principles of bipolar junction transistors (BJT) and metal-oxide-semiconductor field-effect transistors (MOSFET). It discusses MOSFET configurations like common source, common drain, and common gate. It also discusses enhancement mode and depletion mode MOSFETs, and how complementary MOSFETs use both n-channel and p-channel types.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    11 views14 pages

    13-MOSFET - Design and Analysis-24!02!2024

    Uploaded by

    ashbinny1
    The document discusses transistors and MOSFETs. It describes the device structures and operating principles of bipolar junction transistors (BJT) and metal-oxide-semiconductor field-effect transistors (MOSFET). It discusses MOSFET configurations like common source, common drain, and common gate. It also discusses enhancement mode and depletion mode MOSFETs, and how complementary MOSFETs use both n-channel and p-channel types.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 14

    Basic Electronics

    BECE101L

    Module-3: Transistors
    Bipolar Junction Transistor (BJT) - Device structure and physical
    operation, Concept of CB, CE and CC Configuration, Transistor as a
    Switch, - Metal-Oxide Semiconductor Field Effect Transistor (MOSFET)
    - Device Structure, Mode of operation and Characteristics, MOSFET
    configurations (CS, CD and CG).

    Prof. D. Kannadassan, TT 218-3


    dkannadassan@vit.ac.in
    Numerical Simulation: Technology CAD (TCAD)

    100 nm
    Non-saturation and Saturation region
    The region for which vDS < vDS(sat) is
    known as the non-saturation or triode
    region.
    The ideal current-voltage characteristics
    in non-saturation region are described
    by the equation:

    In the saturation region, the ideal current–


    voltage characteristics for vGS > VTN are
    described by the equation

    Where conduction parameter


    for an n-channel device

    And oxide capacitance  OX =  0 r


    Design of MOSFET

     OX =  0 r
    Example 6.1
    Calculate the current in an n-channel MOSFET. Consider an n-channel enhancement-mode
    MOSFET with the following parameters: VTN = 0.4 V, W = 20 μm, L = 0.8 μm, μn = 650
    cm2/V–s, tox = 200 Å, and εox = (3.9)(8.85 × 10−14) F/cm. Determine the current when the
    transistor is biased in the saturation region for (a) vGS = 0.8 V and (b) vGS = 1.6 V.

    Solution: Keep in mind that the units involved in the equations

    The value of the conduction parameter is therefore


    Now we can calculate the current in n-MOSFET, where both (a) and (b) cases
    are above threshold, thus:

    Understand that: The current capability of a transistor can be increased by increasing the
    conduction parameter. For a given fabrication technology, Kn is adjusted by varying the
    transistor width W.
    p-Channel Enhancement-Mode MOSFET

    For the p-channel device

    In the non-saturation region

    In the saturation region

    Where:
    Example 6.2
    Objective: Determine the source-to-drain voltage required to bias a p-channel
    enhancement-mode MOSFET in the saturation region. Consider an enhancement-mode
    p-channel MOSFET for which Kp = 0.2 mA/V2, VTP = − 0.50 V, and iD = 0.50 mA.

    Solution: In the saturation region, the drain current is given by

    That is:

    This yields:

    To bias this p-channel MOSFET in the saturation region, the following must apply:

    Biasing a transistor in either the saturation or the non-saturation region depends on both
    the gate-to-source voltage and the drain-to-source voltage.
    Depletion-Mode MOSFET
    When zero volts are applied to the gate, an n-channel region or inversion layer exists
    under the oxide. The term depletion mode means that a channel exists even at zero gate
    voltage. A negative gate voltage must be applied to the n-channel depletion-mode
    MOSFET to turn the device off.
    Enhancement and Depletion Mode MOSFETs

    Source: S. M. Sze
    Circuit Symbols and Conventions
    The conventional circuit symbol for the n-channel enhancement-mode MOSFET is
    shown in Figure. The vertical solid line denotes the gate electrode, the vertical broken
    line denotes the channel (the broken line indicates the device is enhancement mode),
    and the separation between the gate line and channel line denotes the oxide that
    insulates the gate from the channel. The polarity of the pn junction between the
    substrate and the channel is indicated by the arrowhead on the body or substrate
    terminal. The direction of the arrowhead indicates the type of transistor, which in this
    case is an n-channel device. This symbol shows the four-terminal structure of the
    MOSFET device.
    Three terminal
    Conventional simplified
    symbol symbols
    p-channel MOSFETs

    Depletion Mode MOSFETs


    Complementary MOSFETs

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