Interview with Dr. Steffen Metzger CoolGaN Enters the Mass Market

Integration with GaN and Application-based Reliability Tests

Some competitors are starting to offer not only a single GaN switch, but they also integrate drivers and protection circuitry or even multiple switches as half bridges monolithically on one chip. Does Infineon also have a roadmap in that direction?

We are also working on concepts in this context. One the one hand we are going to integrate drivers onto the chip, on the other hand to integrate several transistors onto one chip. At Infineon, as always, we have to meet all the quality criteria. After that, we will start first projects with a few key customers.

It is a true milestone to manufacture GaN transistors in large volumes as well as in a high level of quality and reliability. This is a solid foundation to build on. Nevertheless, it takes a lot of expertise and effort to create something new from such blocks. I therefore expect that it will take some time to present such a monolithically integrated solution.

When it comes to reliability, you mentioned application-based reliability tests at the press conference here at PCIM. What does this mean?

Typical JEDEC tests prove some of the characteristics of the components. You also place them in a climate chamber, move the temperature up and down either with or without voltage stress and examine afterwards, if they are still electrically OK or if there is some delamination or anything similar.

But these JEDEC tests are not application-oriented. We rebuild the application in our laboratory and keep the components running for a long time under such real-life conditions. In the event of a failure, we analyze the device to identify the fault. Particularly with such a new technology as GaN, as there is not a lot of field experience yet, we have repeatedly discovered completely new failure modes which are not covered by these standard tests. For this reason we always ask our customers for their application profile. So we are able to advise the customer whether the particular device is a good choice for his application or not.

Will these findings be made available to the JEDEC Committee JC-70, which is in charge of test standardization for GaN and SiC?

Of course we will, especially as Tim McDonald is Infineon’s representative on that committee. We definitely want to help to establish standards for GaN.

Besides the high-voltage GaN devices, Infineon's portfolio also includes the low-voltage devices from the legacy of International Rectifier. What is Infineon planning to do in this regard?

International Rectifier's concept relies on a cascode circuit containing a normally-on high-voltage GaN transistor and a low-voltage normally-off silicon MOSFET in series. At Infineon we have decided to solely offer normally-off enhancement-mode GaN transistors.

Does this mean that Infineon will discontinue the IR products?

We have built up inventory from which we are able to serve existing customers. Once this is empty, the normally-off products are ready for shipment.

Besides ON Semiconductor after acquiring Fairchild, Infineon is the only company to offer devices made of both wide bandgap materials GaN and SiC. Is that more of an advantage or a disadvantage?

From the customer’s point of view it is very attractive to have only one partner for all technologies. He is able to provide neutral guidance on the pros and cons of a particular semiconductor technology for the customer’s application. If a customer is contacting a company that only provides gallium nitride, for instance, that company will of course highlight anything in favor of GaN and understate anything in favor of silicon or silicon carbide.

As Infineon, we will position ourselves as a one-stop shop that provides its customers with a comprehensive and neutral approach with regard to semiconductor technology. We do not need to prioritize any particular technology.

But isn't there any competition within Infineon regarding the three technologies?

Sure. There are separate development teams and, of course, each wants to be better or faster as the other. This helps to develop always the best products.

Dr. Metzger, thank you very much for taking the time.