Kyma Launches Their First Device Product: The KO-Switch™

Kyma Technologies, Inc., a leading supplier of crystalline aluminum nitride (AlN) and gallium nitride (GaN) materials and related products and services, today announced they have launched their first device product, the KO-Switch™, which is a high speed, high power, bulk GaN based photoconductive semiconductor switch (PCSS).

The KO-Switch™ provides an exceptional combination of high breakdown voltage, low on-resistance, and fast switching speed. Built from KO-GaN™, which is a specially tailored form of Kyma’s crystalline semi-insulating bulk GaN, the KO-Switch™ is designed to block up to 2,000 volts and to drive 40 amps into a 50 ohm load at 80,000 watts in power when turned on with an appropriate optical beam.

Kyma’s KO-Switch™ development team is led by Chief Engineer Bob Metzger with close support from Chief Scientist Jacob Leach. Recently Processing Technician Devin De Keczer joined the team to assist the commercialization efforts.

The KO-Switch™ responds to all wavelengths in the visible region of the electromagnetic spectrum. Since the bandgap of KO-GaN™ lies in the ultraviolet, excitation of the KO-Switch™ by visible light is called extrinsic excitation. Blue and green light works especially well which makes commercial off the shelf blue and green lasers good excitation source candidates.

Fast switching speed is a key feature of the KO-Switch™. Kyma’s recently established PCSS device testing facility near their corporate headquarters is equipped with a 5 nanosecond pulsed Nd:YAG solid state laser with an optical parametric oscillator that enables continuous wavelength tuning from the near infrared all the way into the near ultraviolet. Kyma’s tests show rapid response of the KO-Switch™ to their laser, providing an upper limit of ~1 nanosecond response time. Indeed, the switch may be significantly faster. To further investigate response time, Kyma provided several KO-GaN™ samples to three independent optical physics experts in the government, academic, and private sectors. The results of their independent investigations were in close agreement and showed an average photoexcited carrier lifetime of 90 picoseconds, with the fastest and longest measured values being 18 and 200 picoseconds, respectively.

“The KO-Switch™ could be a game changer for a number of applications in the medical, homeland security, and defense sectors,” stated Dr. Metzger. “We are currently working with several partners to identify the most promising early adopter applications.”

Kyma President and CEO Keith Evans added, “Bob and Jacob have advanced this exciting new technology at an incredible pace. And none of it would be possible without the vision and support of John Blevins and his colleagues in the Aerospace Components & Subsystems Technology Division of the Sensors Directorate of US Air Force Research Laboratory.”

Kyma is also investigating use of multiple devices in parallel and series and also believes that a 100kV KO-Switch™ device is possible in the near future. Kyma’s technical staff is investigating a number of different PCSS topologies, some of which could be integrated into ultra-high performance GaN based opto-electronic integrated circuits (OEICs). A large design space exists when one considers that sub-bandgap light could be brought into the desired excitation volume in any number of ways, including using waveguides and fiber optics.

For more information about the KO-Switch™ contact Kyma’s Sales Department at

About Extrinsic Photoconductive Semiconductor Switches

Research into extrinsic photoconductive semiconductor switches has been especially active at Lawrence Livermore National Laboratory, Texas Tech University, and University of Missouri-Columbia. More information about wide bandgap (e.g., GaN and SiC) and GaAs extrinsic photoconductive switches can be found in the following references and references therein:

  1. J. S. Sullivan, “Wide Bandgap Extrinsic Photoconductive Switches,” Lawrence Livermore National Laboratory Report LLNL-TH-523591, January 20, 2012, Source
  2. C. James, C. Hettler and J. Dickens, “Design and Evaluation of a Compact Silicon Carbide Photoconductive Semiconductor Switch,” IEEE Transactions on Electron Devices, Vol. 58, No. 2, February 2011
  3. J. Yuan, W. Xie, H. Liu, J. Liu, H. Li, X. Wang, and W. Jiang, “High-Power Semi-Insulating GaAs Photoconductive Semiconductor Switch Employing Extrinsic Photoconductivity,” IEEE Transactions on Plasma Science, Vol. 37, No. 10, October 2009
  4. K. S. Kelkar, N. E. Islam, P. Kirawanich, C. M. Fessler, and W. C. Nunnally, “ON-State Characteristics of a High-Power Photoconductive Switch Fabricated From Compensated 6-H Silicon Carbide,” IEEE Transactions on Plasma Science, Vol. 36, No. 1, February 2008

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 ~$9B in 2011 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.