Steve Lester
Chief Technical Scientist, ExaGaN


Dr. Lester is a senior executive and technologist in the field of compound semiconductor materials, devices, and applications. In recent years he served as CTO of Bridgelux, Inc., a GaN LED lighting manufacturer. There he led the development of the first 200mm GaN-on-Si LED’s and negotiated a joint development relationship with Toshiba for commercialization of the technology. In 2013 he joined Toshiba as Vice President in charge of GaN development for LEDs and Power Electronics. There he oversaw the largest investment ever in GaN-on-Si. In 2017, Dr. Lester joined Exagan as Chief Technical Scientist overseeing the company’s introduction of GaN power electronics components based on CMOS-compatible 200mm manufacturing.


After many years of development across the globe GaN is now being adopted into power electronics switching applications. Its inherent high power handling capability, high-temperature operating range, and high switching speed is unmatched compared to Si or SiC-based solutions. Wide-spread adoption of GaN-based solutions, however, will not only depend on performance, but also cost and manufacturability. At Exagan, we have developed a 200mm fully CMOS-compatible epi and fabrication process for HEMTs targeting 650V applications. High-performance, low-dispersion 650V lateral HEMTs have been realized with functional yields meeting Si manufacturing standards and their performance has been validated in a wide variety of applications.