Chips keep their cool at 300°C

The technique was discovered by a team led by Holger Kappert from the Fraunhofer Institute for Microelectronic Circuits and Systems. While previous attempts to increase operating temperature range have resulted in increased chip size and/or limited performance, Kappert says there are no such trade-offs with this technique. At a characteristic dimension of 0.35µm, the chips developed by him and his team are considerably smaller than the high temperature chips available today. To fabricate them, the researchers used a specialised high temperature SOI CMOS process. "SOI stands for silicon on insulator – that means we introduce a layer that insulates the transistors from one another," explained Kappert. This insulation prevents leakage currents that occur from influencing the operation of the chip. The researchers also used tungsten metallisation, which is less temperature sensitive than the aluminium usually used and increases operating life. Kappert believes the chips could prove valuable to the aerospace sector, by enabling sensors to be located as close as possible to turbine engines in order to be able to observe the state of their operation. The first field tests have been positive. The researchers want to offer the fabrication process as a service later this year.