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spread use as a material for lead frames, while new inte- grated heatsinks with AlSiC or SiN direct-bonded copper substrates are becoming standard.
Finally, solder plays a role in increasing module reliability, especially at higher temperatures. The use of gold/tin sol- ders or silver sintering is becoming increasingly common and can be found at different levels: under the die, under the sub- strate, or on the baseplate.
All these innovations have a cost, so manufacturers must take this into account. A bigger power module using SiC can have a higher cost by itself, but it is also essential to consider the final impact on integration and assembly flex- ibility. The rapid evolution of technology at all design levels and the cost of modules are the two factors that have elimi- nated the presence of a standard in power module design in recent years, and we expect even more innovation in the
SiC is expensive compared with silicon, but its performance advantages are compelling end users to choose it more often.
future. The requirement for cost saving during integration drives design companies to move to single and more flexible structures, such as one-in-one commutation cells or embed- ded discrete. As a direct consequence, the SiC power module packaging supply chain is changing drastically.
The technical challenges linked to SiC device developments have also impacted the supply chain. While at the early stage of SiC devices, only a few players, such as Cree, were able to produce substrate and epitaxy. Increasing interest in these devices in recent years has motivated the big players to form partnerships and to consolidate, enabling internal produc- tion. This has been the case for Rohm, with its acquisition of SiCrystal, and for STMicroelectronics, with the acquisition of Norstel.
In summary, the development of SiC power device technol- ogy will be driven by the overall market growth in specific segments. In the short- to mid-term, the focus will be on 1,200-V components. Even within this voltage class, how- ever, different applications have different requirements, so a one-size-fits-all technology will probably not be enough. The key aspect for chip and package developers will be to pro- vide room for sufficiently broad parametric tradeoffs within a given base technology to realize the application-specific product requirements of a wide range of applications.
Obviously, all these innovations have a cost, which manu- facturers must take into account. An innovating technology can have a higher cost by itself, but the impact on the inte- gration and flexibility of the final system must also be con- sidered. Although SiC power device technology initially was very expensive due to the improvements in base material, die design, and new packaging solutions, we expect that the costs will decline significantly and must continue to do so in the future to ensure wider market adoption.
Elena Barbarini
is director of the semiconductor devices department at System Plus Consulting, part of Yole Développement.
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Technology Analysis Silicon Carbide: Beyond the Design and Packaging