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Silicon Carbide power diodes specifically designed for BepiColombo and Solar Orbiter satellites

When BepiColombo reaches Mercury, it may experience temperatures in excess of 350ºC.

 

The Silicon Carbide power diodes were specifically designed for protection of solar cell arrays in solar panels mounted in satellites and space exploration modules. The first batches of devices are currently being used in two European Space Agency missions, BepiColombo and Solar Orbiter.

This diode is very small, 3,1 x 1 x 0,6 cm, to be more precise.

These diodes, developed by CSIC with the collaboration of ALTER TECHNOLOGY (ATN), are remarkable in respect of their unusually wide operating temperature range, from -170ºC up to 300ºC which is made possible by the use of silicon carbide instead of silicon as the bare material. Silicon carbide is what is known as a Wide Band Gap semiconductor and is superior to silicon in respect of its electrical and physical characteristics, making it particularly suitable for high-power, high-temperature and high-frequency electronic applications. Silicon carbide is currently being used in power electronics applications such as hybrid and electric cars, renewable energies, power supplies, train transportation, albeit in a standard operating temperature range from -40ºC up to 175ºC.

In addition to the use of silicon carbide as semiconductor material for high temperatures, a specific and robust processing and packaging technology has been developed. The internal device structure differs from standard commercial SiC diodes. The interconnections and the package have been optimised specifically for the semiconductor die to take full advantage of the SiC-intrinsic performances. ATN has been in charge of the electrical, environmental and reliability test campaigns. The feedback from ATN studies helped to optimise the final design and fabrication process of the device. As the operating range of these devices was unusual, no characterisation standards were available, and current ESA ESCC standards have been adapted by ATN and ESA specialists. A specific screening and qualification campaign has been designed and carried out. This can be used as a base line for the future definition of test standards for novel high-temperature devices.

This device is the first Spanish component to be included in the European Space Agency European Preferred Part List (EPPL). However, the diodes could also be used in other high-temperature applications.

Space-qualified silicon carbide power diodes have been developed by the CNM-CSIC power group in Barcelona in close collaboration with ATN, produced by D+T Microelectrónica in the CNM-CSIC facility (ICTS) and qualified by the ALTER TECHNOLOGY Optoelectronics large-scale and New Technologies division in Tres Cantos (Madrid). From now on, these parts will be treated as products specific to ALTER TECHNOLOGY for markets requiring high reliability and the ability to withstand harsh environments.