Suvarna Garge (Editor)

Gate dielectric

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Gate 2015 ece process used to form the gate dielectric or gate oxide or thin oxide


A gate dielectric is a dielectric used between the gate and substrate of a field-effect transistor. In state-of-the-art processes, the gate dielectric is subject to many constraints, including:

Contents

  • Electrically clean interface to the substrate (low density of quantum states for electrons)
  • High capacitance, to increase the FET transconductance
  • High thickness, to avoid dielectric breakdown and leakage by quantum tunneling.
  • The capacitance and thickness constraints are almost directly opposed to each other. For silicon-substrate FETs, the gate dielectric is almost always silicon dioxide (called "gate oxide"), since thermal oxide has a very clean interface. However, the semiconductor industry is interested in finding alternative materials with higher dielectric constants, which would allow higher capacitance with the same thickness.

    Gaas mosfet with oxide gate dielectric grown by atomic layer deposition


    References

    Gate dielectric Wikipedia