MOSFET driver circuit configuration for half bridge MOSFETs for power amplifier
Several things wrong with that design!


Where is the decoupling? That 15V line needs a whole pile of cap on it.... 
C4???! 22uF for a boost cap, just insane, get rid of it, the 220n should be fine on its own. 
R13/14 1k, try more like 100k.
Those mosfets, 140nC maximum gate charge?! Yea they are very, very butch fets, but you really want something much smaller and with a very much lower Qg.
Layout? It really, really matters. 
Not the cause of the blowup, but R11/12 seem very high in value, especially given the Qg of those mosfets.