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  1. #1
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    What is Halo Implant Shadowing?

    I've read Halo Implant Shadowing and Backscattering can affect leakage current but do not understand the effect itself. Can someone please explain it or point me to a reference?

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  2. #2
    Advanced Member level 5
    Points: 39,692, Level: 48

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    Re: What is Halo Implant Shadowing?

    Ion implantation is probabilistic, in where the ions end up,
    and "hard mask" features are able to affect this too.

    Halo implants tend to be shot at oblique angles from
    normal so they can "reach under" spacer. If gates are
    too tightly packed, it becomes sort of like getting sunshine
    on the sidewalk, downtown - some places are better
    than others, depending on the neighbors.

    A local weakness in the halo implant will raise that device's
    leakage. If too many ions bounced off (backscatter) or
    were caught before target depth (shadowing) the halo
    shot will be weakened.

    Halo works by stiffening the body doping and pushing
    harder into the LDD at higher drain-body voltages (a
    JFET action).



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