STMicroelectronics is backing multiple approaches to wideband semiconductors for power applications. While driving silicon carbide for automotive power devices, it has also announced a key deal with foundry TSMC for gallium nitride power devices.
This is interesting, as the company also has two types of GaN technology in-house and the TSMC deal adds a third. The first, developed with MACOM, is used on 150mm (6in) wafers for RF power devices. The second was developed for 200mm (8in) wafers with French research lab CEA-Leti. Both are made at the French fab at Tours.
Back in March 2019, Marco Monti, president of ST’s Automotive and Discrete Group. said the first GaN power parts from Tours using the Leti process would be available by the end of the year. This has now slipped, albeit slightly, to engineering samples of discrete power devices by the end of Q1 2020 with Smart Power versions by Q1 2021.
“This cooperation complements our existing activities on power GaN undertaken at our site in Tours, France and with CEA-Leti,” he said. “GaN represents the next major innovation in Power and Smart Power electronics, as well in process technology”.
Perhaps this accounts for the agreement to use TSMC’s GaN process for both discrete power devices and integrated ‘smart power’ devices on 150mm wafers. Mass production of 650V discrete GaN power devices will start at TSMC in Q1 2021, a year after the first device comes out of Tours. The 100V parts will follow a year after that, which looks very much like the route for future process development and cost reductions through volume production. “TSMC is a trusted foundry partner that can uniquely meet the challenging reliability and roadmap evolution requirements of ST’s target customers,” said Monti.
The mention of reliability is telling, as the pioneers in the GaN power device market such as EPC, GaN Systems and Transphorm have had to work