I'd argue Research Triangle Park (RTP) is better choice than Austin. Instead of using one feeder school Amazon could pull from three excellent schools: Duke University, North Carolina State University, and University of North Carolina at Chapel Hill. For those that are unfamiliar RTP is a major tech center.
Edit: Changed "RTP" to "Research Triangle Park" in initial comment.
Edit: Changed "RTP" to "Research Triangle Park" in initial comment.