Keying halo

[emmaTPR12]

I'm trying to make the best of some footage I've been asked to use, which has various talking heads shot in front of a green screen. One of the speakers has very fair hair and I can't get a good enough key in Premiere where I'm editing the project, so I've brought it into AE. I've been tweaking the settings for about an hour and I still can't get rid of this halo effect that is outlining her:

Any suggestions appreciated. Thank you.

[Mylenium · Accepted solution]

That's what the Refine Edges effect is for...

Mylenium