Kyma Reports Initial KO-Switch™ Device Reliability Results

Kyma Technologies, Inc., a leading supplier of crystalline aluminum nitride (AlN) and gallium nitride (GaN) materials and related products and services, today announced the completion of their initial investigation of the reliability of the device performance of the recently launched KO-Switch™.

Kyma first announced the launch of the KO-Switch™ as their first device product in September of last year, which was made possible from an Air Force Research Laboratory (AFRL) R&D investment managed by John Blevins of AFRL and led by Bob Metzger, Kyma’s Chief Technology Officer.  Characteristics of the device operation were presented last month at Photonics West 2013 by Jacob Leach, Kyma’s Chief Science Officer.

A natural next step in studying the characteristics of the KO-Switch™ is to measure how stable its performance is under various device operating scenarios. Since many of the applications that the KO-Switch™ are being considered for require impedance matching at the 50 Ω resistance level, it is interesting to operate the KO-Switch™ under conditions that target an on-resistance (Ron) near 50 Ω and to see if Ron drifts over time or as a function of another variable such as operating temperature. Additionally, the fast switching speed of the KO-Switch™ becomes a real benefit for many applications if the device can be switched on and off thousands or even millions of times without significant degradation.

With such matters in mind, Dr. Leach and Dr. Metzger designed a test to repeatedly turn the KO-Switch™ on and off over 1,000,000 times while monitoring Ron and measuring the current through the device which was biased at 1,000 volts (in the off condition). The 532 nm excitation laser was adjusted to excite the device with 5 nanosecond wide pulses in a 10 Hz pulse train and was coupled to the device to set the initial Ron = 20 Ω. Instantaneous current passing through the 2 mm diameter device was 50 A while the switch was closed. After subjecting the switch to >1,000,000 close/open cycles, the change in Ron was less than 1%, which is within the error of the measurement system. The conclusion is that there is no noticeable degradation in Ron after 1,000,000 device operations.

Dr. Leach commented, “We are very encouraged at the excellent reliability we find under these operating conditions, which are relevant for several different customer applications. Next we want to begin pushing the device harder, at higher currents and laser pulse energies, for example, and under higher bias voltage. I am confident we will find the edges of its reliability behavior which will inform our future device improvement plans.”

Dr. Metzger added, “We believe these are the first publically disclosed device reliability results obtained on a wide bandgap photoconductive switch. This is an exciting new product space for us to get involved in and we look forward to seeing how far we can take the switch in terms of high performance applications.”

Leach and Metzger are in the process of preparing a scientific publication that will describe the details of the device reliability study.

Kyma has sold several units of the KO-Switch™ already in 2013 and is working with a number of large companies to understand its potential to support several high performance high power switching applications. 

About Kyma Technologies

Kyma is a leading provider of crystalline nitride semiconductor materials, device, and equipment solutions for energy efficient lighting and electric power management.

The market for nitride semiconductor devices was ~$10B in 2012 and is expected to surpass $60B over the long term, including $30B in visible lighting applications and $30B in power electronics applications.

For more information about Kyma Technologies, visit, e-mail, or call the company directly at 919.789.8880.

Kyma is a registered trademark of Kyma Technologies, Inc.