Overview
Power transistors are used in power supplies, which are a fundamental part of spacecraft electrical systems. Gallium nitride (GaN) transistors are an ideal choice for spacecraft power supplies and mission equipment owing to the material’s high breakdown strength, fast switching speed and high thermal conductivity. Furthermore, GaN transistors allow reductions in power consumption and in the equipment masses. Europe’s shortage in such types of transistors is likely to become more critical as reliance on external suppliers continues to grow.
The EU-funded SAGAN project seeks to establish an independent supply chain for GaN transistors covering the design, manufacturing, processing and qualification testing. The transistors will be tested to assess radiation effects, thermal dynamics, structural behaviour and reliability. The SAGAN proposal addresses a crucial element in future satellite platforms and payloads. Spacecraft Electrical Power Systems (EPS) are a key element that enable space missions. Without an efficient EPS, many of the capabilities that we take today for granted, such as high-speed communications, GNSS and science payloads, would not be possible.
Power transistors are key elements of the electrical units that form the EPS and other systems, since they allow the most efficient (in terms of power and mass) electrical power processing topologies. During the last decade, several technological advancements have enabled a new type of transistors based on Gallium Nitride over Silicon. GaN transistors allow a reduction in mass of the equipment that uses them and a reduction in power consumption.
Currently, Europe does not have the capabilities to produce GaN transistors for space unless relying on external countries for most of the supply chain, which is something that cannot be taken for granted. The objective of the SAGAN proposal is to overcome this situation by establishing a non-dependent supply chain (design, manufacturing, processing, and qualification testing) for GaN transistors that are suitable for space applications. The transistors will be tested to assess radiation effects, thermal dynamics, structural behaviour, reliability...
To achieve it, a strong consortium has been established. It is composed by organisations that have the knowleadge and the facilities to fulfil the objective. The consortium is composed of a company devoted to space level GaN transistors and integrated circuit design (SEMI ZABALA), a research foundry (IMEC), a company that processes wafers to the standards required by the technology (DISCO HI-TEC) and a satellite equipment manufacturer with component packaging capabilities (SENER). The consortium also counts with the role of GaN transistor end user, which is played by SENER as spacecraft equipment manufacturer.