Other Fabs are already located in the area, and in general the state has been good towards businesses. Also ASU is nearby so they have a talent pool of new engineers to pull from.

Anecdote, since I've moved to AZ myself 5 years ago I've noticed massive growth in tech businesses in Phoenix and the surrounding areas. Cost of living for people here is also cheaper compared to to other cities I've lived in, and many people I've met who moved from California have told me how its cheaper here. Commuting is not too bad depending on where you live, and there are options which promote commuting or carpooling such as HOV lanes, Bike Lanes, and the light-rail system (the light rail is hit or miss depending on who you ask).