“silicon on PDMS”: SOI extra thin active layer transferred to organic film for flexible applications

This paper presents the fabrication for transferring an SOI LSI chip to organic flexible material like PDMS (poly-dimethyl-siloxane). The test chip has 60 nm- thick active layer, 200 nm BOX (buried oxide) layer and 9 mum 5-layer metals of 0.15 mum technology. The fabrication also included the process of building electrode contacts by etching through buried oxide (BOX) layer to metal layer. The SOI chip with original thickness of 500 mum was embedded in PDMS and thinned to less than 10 mum thick. The structure of active layer, contacts and other interconnection patterns of SOI chip are seen through, because silicon oxide as insulator is transparent. In addition, this silicon on PDMS devices are bendable because they were extremely thin and placed on flexible PDMS. Transistor characteristics were measured, showing slight decrease in S-factor but increase in maximum current after process, and slight decrease after bending.