Technology

Kyma Technologies uses several advanced crystal growth and crystal processing technologies to fabricate its growing portfolio of crystalline and polycrystalline nitride semiconductor materials products.  Kyma's patented and proprietary crystal growth technologies include hydride vapor phase epitaxy (HVPE) and physical vapor depositon (PVD).  For fabrication Kyma utilizes various patent-pending and proprietary sawing, grinding, and polishing technologies.

Kyma free-standing, or native GaN substrates are sliced and polished from single crystal boules of GaN produced by HVPE.  Kyma's GaN and AlN templates are produced using combinations of HVPE and PVD technology.  Kyma's polycrystalline GaN materials are produced using a modified HVPE process.

For each of Kyma's product the emphasis is on producing the best possible materials at the lowest possible manufacturing cost.  This way we help our customers continuously improve the quality and cost of their epiwafers and devices.

Kyma native GaN substrates have world-class defect densities, which translate to improved structural, electrical, and thermal properties in the device active region.

Kyma's GaN and AlN templates are used where a lower substrate price is required but where benefits in active region properties is required relative to growth on foreign substrates.  Kyma's GaN templates also provide clear benefits in terms of defect density and thermal conductivity.  Such benefits appear to be possible as well using Kyma's AlN templates, although the company is still collecting data in the latter case.

Thermal Conductivity Matters: An often misunderstood factor in epitaxial nitride materials is the dependence of the thermal conductivity of the active region and the buffer layers on defect density.  In a close collaboration with Professor John Muth's group at NCSU's Electrical and Computer Engineering Department, Kyma has found and published the strong dependence of thermal conductivity on defect density.*  These studies find that the thermal conductivity in Kyma's native GaN is over twice that of GaN in a typical nitride semiconductor device grown on sapphire, silicon carbide, or silicon.

*C. Mion, J. F. Muth, E. A. Preble, and D. Hanser, "Accurate dependence of gallium nitride thermal conductivity on dislocation density," Appl. Phys. Lett. 89, 092123 (2006).