I'm in the process of making a mask for a GaN HFET process and want to make sure that I'm not missing anything before sending the design off.  

I fully understand the basics of an FET especially the inner workings of a GaN HFET but my knowledge of scaling it up for use in high current circuits is lacking.

Could anyone suggest a book or research publication that reviews of different power transistor mask designs? I'm looking for examples of interdigitation, contact bridging, surface passivation, etc. and the pros/cons of each design choice.