Integrated heat sinks for SOI power devices

Silicon on insulator (SOI) technology for power devices offers many distinct advantages compared to bulk Si technology, however in high power applications the buried oxide (BOX) layer can impede heat transport towards the backside of the silicon substrate. This paper demonstrates integration of heat sinks in SOI power devices to improve thermal performance. The heat sinks are formed by polysilicon plugs through the BOX layer that significantly reduce thermal resistance and thus increase the safe operating limits of the technology. The effectiveness of the integrated heat sinks was evaluated by the experimental AC conductance method and by thermal finite element modeling. The integrated heat sinks are shown to reduce the thermal resistance by 15%, improving both thermal and electrical performance of the SOI transistors.