Oskar Fajerson | Polar Light Technologies AB: Can bottom-up MOCVD growth eliminate the dreaded microLED sidewall damage?
00:02:11 - 00:03:54
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Can bottom-up MOCVD growth eliminate the dreaded microLED sidewall damage?
Standard top-down fabrication of microLEDs relies on reactive ion etching (RIE) to singulate pixels, which introduces severe physical and chemical damage to the mesa sidewalls. This process creates high-density dangling bonds and non-radiative recombination centers, causing a catastrophic drop in internal quantum efficiency (IQE) as pixel dimensions scale down.
Polar Light Technologies bypasses this limitation entirely using a mask-directed, selective-area epitaxial growth of pyramidal structures in an MOCVD reactor. Because the facet planes of the pyramids are naturally formed during the growth phase, the active InGaN/GaN multi-quantum wells (MQWs) are completely free from defect-inducing dry-etch processes.
This epitaxial approach also opens a revolutionary path to monolithic RGB on a single substrate. By altering the growth dynamics and mask geometries, the indium incorporation efficiency of the quantum wells can be spatially controlled, enabling blue, green, and red emitters to be grown side-by-side using a single material system without the need for complex mass transfer of different material families.
In this short video, you can learn:
* How selective-area MOCVD growth of pyramidal structures prevents sidewall defect creation.
* The mechanism behind achieving monolithic RGB integration without color-conversion layers.
* Scaling benefits of bottom-up structures compared to conventional top-down mesa etching.
๐ **Clip Abstract** This clip explores the bottom-up pyramidal microLED architecture developed by Polar Light Technologies, highlighting how it eliminates etching-induced sidewall damage. The discussion explains how selective MOCVD growth allows side-by-side monolithic integration of RGB emitters on a single material system.
#SelectiveAreaEpitaxy, #PyramidalMicroLEDs, #MonolithicRGB, #BottomUpEpitaxy, #MicroLEDDisplays, #ARDisplays
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00:04:00 - 00:05:22
Why is Lambertian emission the silent killer of AR waveguide efficiency?
Why is Lambertian emission the silent killer of AR waveguide efficiency?
Traditional planar microLEDs emit light in a broad Lambertian profile, scattering photons across a wide angular distribution. For near-eye displays and augmented reality (AR) architectures, only a tiny fraction of this wide-angle light falls within the acceptance angle (numerical aperture) of the optical waveguides, leading to severe etendue mismatch and systemic power waste.
Polar Light Technologies leverages the intrinsic geometry of their micro-pyramids to act as natural refractors, achieving a highly directional, sub-Lambertian emission profile. By shaping the wavefront at the generation site, the photons are directed into a much narrower angular cone, maximizing the coupling efficiency into downstream optics.
Empirical data demonstrate that at a green wavelength of 520 nm, the pyramidal emitters concentrate up to 58% of the total emitted light within a narrow plus minus 20-degree cone. This represents a massive leap in end-to-end system efficiency, ensuring that precious milliwatts of battery power translate directly into readable nits at the user's eye.
In this short video, you can learn:
* The physical limitations of Lambertian emission in planar microLED structures for AR optics.
* How the geometry of pyramidal microLEDs naturally shapes and collimates light.
* Empirical data showcasing a green emitter concentrating 58% of light within a plus minus 20-degree cone.
๐ **Clip Abstract** This segment highlights the critical role of sub-Lambertian light emission in optical waveguide coupling for AR microdisplays. The speaker presents empirical data demonstrating how pyramidal structures achieve directional focus to prevent system efficiency losses.
#SubLambertianEmission, #PyramidalMicroLEDs, #WaveguideCoupling, #EtendueMatching, #ARMicrodisplays, #NearEyeOptics
00:11:47 - 00:12:40
Is the microLED industry pushing sub-micron scaling before CMOS backplanes are even ready?
Is the microLED industry pushing sub-micron scaling before CMOS backplanes are even ready?
While the research community frequently celebrates the fabrication of sub-micron microLEDs, actual commercial viability is bottlenecked by backplane integration. Driving sub-micron pixels requires high-density CMOS active matrices with sub-micron pixel circuits, which face immense challenges in current leakages, parasitic capacitances, and routing density.
Polar Light Technologies has demonstrated the technical feasibility of scaling their pyramidal structures down to an astonishing 300 nanometers. However, from a strategic product roadmap perspective, their initial market entries will target sizes above one micron to align with existing CMOS driver capabilities and backplane design rules.
This pragmatic commercial approach ensures that research and development efforts are synchronized with the display ecosystem's maturity. Developing sub-micron emitters yields excellent academic insights, but real-world deployment requires a holistic view of the entire display engine stack, from epitaxial growth to active-matrix CMOS driving.
In this short video, you can learn:
* The stark contrast between laboratory sub-micron microLED feasibility and commercial driver limitations.
* Polar Light Technologies' strategic roadmap targeting greater than 1-micron devices first to align with backplane readiness.
* The technical challenges of active-matrix CMOS driving at the sub-micron scale.
๐ **Clip Abstract** The speaker addresses the pragmatics of sub-micron scaling and the commercial realities of microdisplay integration. He explains why Polar Light Technologies is focusing its product roadmap on sizes above one micron to match current CMOS backplane capabilities.
#SubMicronMicroLEDs, #CMOSBackplanes, #ActiveMatrixDrivers, #PyramidalLEDs, #ARMicrodisplays, #NearEyeDisplays