Vertical GaN is a power semiconductor technology where current flows vertically through a GaN-on-GaN structure rather than laterally across the surface, enabling much higher breakdown voltages, current densities, and switching speeds in a compact device. By using bulk GaN layers on native GaN substrates, it reduces defects, improves thermal handling and avalanche robustness, and cuts switching and conduction losses, making smaller, lighter, more efficient converters for applications like AI data centers, EV inverters, renewable energy systems at 650–1200V, and potentially LEDs.
Vertical GaN structures have been applied to LEDs, particularly in high-power and micro-LED formats. Research and prototype devices include vertical GaN-based UV LEDs on Si, vertical GaN blue LEDs, and GaN-on-GaN vertical micro-LEDs for near‑eye AR/VR displays, leveraging the same vertical current flow and GaN-on-GaN benefits used in power devices.
For general illumination, vertical GaN LEDs are most likely to impact the upper end of the market first (high‑luminance, high‑power, or value‑differentiated products), while commodity lamps and panels will stay lateral for quite a while.
Vertical GaN LEDs offer better current spreading and thermal paths, enabling higher drive current, higher lumen density per chip, and improved reliability at high power levels. This favors applications like high‑bay/industrial, outdoor area, street/architectural, and automotive‑style forward lighting more than A‑lamps or troffers, where current lateral LEDs already meet performance and cost targets. Higher brightness per die can reduce the number of chips per engine, enabling more compact optics and form factors in premium luminaires.
Better thermal and electrical robustness at chip level can reduce over‑engineering in heat sinks and drive electronics, enabling lighter, smaller, and potentially cheaper premium luminaires even if die cost is higher. Optical architectures may evolve toward fewer, brighter emitters per engine, which affects secondary optics vendor relationships and potentially simplifies module assembly. Reliability gains from lower defectivity substrates and improved heat dissipation can translate into longer warranties or more aggressive lifetime specs, a differentiator in professional and infrastructure lighting.
Vertical GaN device architectures will gradually push LED manufacturing toward higher-brightness, higher‑density, and more power‑capable products, but they also force significant changes in substrates, process flow, and capex.
Vertical current flow improves current spreading, reduces current crowding, and supports higher drive currents compared with lateral LED layouts, which enhances lumen output and reliability at high power. Using GaN‑on‑GaN or other homoepitaxial vertical stacks drastically lowers dislocation density versus GaN‑on‑sapphire, boosting efficiency and lifetime, especially under high current density (micro‑LEDs, high‑power chips). Vertical micro‑LEDs on conductive GaN substrates show higher effective EQE at high brightness and maintain performance at small pixel pitches, which is critical for AR/VR near‑eye displays. Improved thermal paths (heat flowing through a conductive GaN or Si carrier rather than sapphire) allow higher junction power density and more compact chip sizes without thermal runaway.
Vertical GaN architectures can deliver more lumens (or nits) per unit area and per die, so at the system level they may reduce die count and packaging complexity despite higher per‑wafer cost. For micro‑LED displays, vertical GaN on homoepitaxial GaN significantly simplifies or eliminates transfer/thinning steps, which are major yield and cost bottlenecks today, enabling more scalable high‑resolution panels. Higher device robustness and thermal stability at high power can relax some packaging constraints (e.g., less over‑designed heat sinking), shifting system‑level BOM cost distributions. The capex profile raises the barrier to entry: fabs need vertical‑process capabilities (implant, wafer bonding, precision grinding, backside litho/metallization) in addition to standard MOCVD and front‑side tools.
Progress in vertical GaN for power devices (high‑voltage GaN‑on‑GaN transistors and diodes) is driving improvements in low‑defect bulk GaN substrates and epitaxy that LED manufacturers can leverage. Shared substrate and epi supply chains between vertical power GaN and vertical LEDs will likely improve availability and cost of bulk GaN over time, making vertical LED architectures more viable for mainstream lighting, not just niche micro‑displays. Lessons in reliability and ruggedness from high‑voltage vertical GaN (e.g., handling thermal and voltage stress) map directly into high‑power LED emitters for automotive, projectors, and UV/industrial applications.
Existing high‑volume LED lines optimized for lateral GaN‑on‑sapphire will face a classic “innovator’s dilemma”: retrofit for vertical (especially for micro‑LED and high‑power segments) or keep lateral for commodity illumination and signage. Early movers building vertical GaN capability (particularly GaN‑on‑GaN micro‑LED for AR/VR and specialized high‑power emitters) gain differentiation on brightness, pixel density, and efficiency that is hard to match with lateral architectures. Over the medium term, expect a bifurcation: commodity LEDs remain lateral, while premium segments (micro‑display, automotive, projection, UV‑C, very high‑luminance sources) migrate to vertical GaN architectures as substrate cost and process maturity improve.
More information is available here.
Image above courtesy of onsemi.com.
You must be logged in to post a comment.