Aluminum-nitride thin-film heatspreaders integrated in bipolar transistors

Aluminum nitride heatspreaders are demonstrated to provide a large reduction of the thermal resistance of silicon-on-glass bipolar junction transistors. 3-D thermal-only simulations are performed to show the further benefit that can be achieved by combining deposited aluminum-nitride layers as heatspreaders with copper heatsinks. Compared to a reference device, a reduction of more than 90% in the value of thermal resistance can be obtained when the transistor is sandwiched between two layers of AlN, one deposited on the frontside of the wafer (front-wafer) and one on the backside of the wafer (back- wafer) of thickness 6 mum and 4 mum, respectively, and a Cu block of 4times70times70 mum³ is added.