Transphorm Releases High Voltage GaN Reliability Data
Company surpasses 10B field hours of operation; reports year-on-year FIT rate reduction to less than one
Transphorm, a supplier of high reliability, high performance GaN power conversion products, has released updated information regarding its GaN technology's quality and reliability (Q+R).
Currently, Transphorm's GaN platform offers a FIT rate of < 1 failure per billion hours in real-world applications—indicating very high reliability. The FIT calculation is based on more than 10 billion (10B) field hours of operation accumulated from an install base of approximately 250 megawatts (MW).
Transphorm's devices are in use today across a wide range of applications spanning 65 W to 3 kW. Examples include universal, fast charging adapters for smartphones and laptops; rugged, broad industrial power modules; and 1.5 to 3.0 kW Titanium class data center power supplies, which meet the high power efficiency ecodesign requirements mandated by The European Parliament and The Council (ErP: Directive 2009/125/EC).
Transphorm GaN v. SiC Reliability
SIC power devices are an alternative power conversion solution and in a later stage of maturation than power GaN solutions. Although SiC offers more than a trillion hours of field operation compared to Transphorm GaN's 10B hours due to being commercially available longer, recent reports indicate that SiC's Field Failure FIT rate is 4.1. This illustrates the high field reliability achieved to date by Transphorm's GaN with a FIT of < 1.
In-house Reliability = In-field Reliability = Accuracy
Extrinsic Reliability, also referred to as Early Life Failure (ELF) or Infant Mortality, is determined via in-house manufacturer analysis - identifying material, design, and process control defects that may cause parts to fail. Alternatively, Field Failure measures the number of devices that fail in customer systems in production in relation to the total number of parts sold.
When assessing FIT rate, the above two metrics - ELF and Field Failure - are studied. The convergence of these two rates means a semiconductor manufacturer's internal reliability assessments are accurate; a customer can have confidence in that reported level of device performance.
In January 2019, Transphorm announced a Field Failure FIT of 3.1. Later in 2019, the Field Failure FIT decreased to 2.2. And, today, Transphorm's Field Failure FIT of < 1 aligns closer to its current ELF FIT rate of 0.61.
For customers, knowing the ELF statistics of a technology is essential to controlling warranty claims. Transphorm follows the standard industry practice as defined in JEDEC's JESD74A standard for measuring its Early Life Failure rate. Ensuring conservative results, Transphorm tests its devices to their maximum spike rating and an appropriate use temperature of 85degC. Despite JEDEC qualification requiring Early Life Failure rate testing, only Silicon device manufacturers commonly report it—most GaN and SiC power electronics manufacturers do not.
“To the best of our knowledge, Transphorm is currently the only high voltage GaN semiconductor company to report ELF,” said Ron Barr, VP of Quality and Reliability, Transphorm. “We understand that customers require certain information when comparing wide bandgap technologies. So, we aim for transparency here. And accuracy, as we frequently see reliability data being calculated differently or manipulated in uncommon ways yet being reported as the same metric type. Given this trend, our education efforts are focused heavily on explaining the proper methods that must be used to prove business-critical metrics and why.”