Development of high-throughput, multi-scale porosity-dependent inspection of porous wafer and microLED chips
MicroLED display technology offers a huge performance improvement with optimal brightness, efficiency, image definition, and extended lifespan. However, achieving high-efficiency, ultra-fine-pitch pixels for multiple-colour displays has been a longstanding challenge.
Porotech is an emerging Gallium Nitride (GaN) material technology developer and a spin-out from the University of Cambridge. Porotech offers a solution based on the proprietary porous GaN technology, PoroGaN(r). This technology introduces nanopores (10-50 nm) into epitaxial film (50nm-5um) at wafer-scale (6, 8, 12 inches). It provides a broad range of pore sizes, porosity, and structures, offering a dramatically new combination of optical, mechanical, thermal, and electrical properties. Consequently, it opens up new horizons for device engineering. The PoroGaN(r) products are currently used for delivering Porotech's disruptive DynamicPixelTuning (DPT(r)) microdisplay product.
Porotech is embarking on an innovative project to develop high-throughput, multi-scale porosity-dependent inspection techniques for porous wafers and microLED chips. Leveraging our proprietary PoroGaN(r) material platform, this project addresses the critical need for comprehensive, high-resolution inspection of PoroGaN(r) wafers and microLED chips, essential for our mass production. The technological challenge lies in controlling the quality of these wafers through advanced inspection methods that provide accurate measurements of optical, electrical, and thermal behaviours across various scales. By integrating advanced photoluminescence (PL) mapping, ellipsometry spectroscopy (ES), and electroluminescence (EL) mapping, in combination with reflectance and micro-EL spectroscopy, and sophisticate data analysis approach, we aim to achieve comprehensive analysis of the surface defects, structural, and optical properties of the porous wafers and microLED chips, making it a pioneering effort in enhancing microLED manufacturing processes. Currently we lack of access of facilities to measure optical/electrical/thermal properties of microLED at multiple-scales. This project will leverage the expertise and facilities of the National Physical Laboratory (NPL) to address critical measurement challenges, ultimately enhancing Porotech's manufacturing capabilities and positioning the UK as a leader in the compound semiconductor industry. The high-throughput inspection methods developed during this project will significantly reduce our in-house development costs, saving approximately £600k. This will translate into an increased margin of over £1M in the following years due to higher product quality and yield, as well as cost savings from more efficient manufacturing processes. Additionally, the standardisation of wafer-scale inspection tools for porous wafers will be the major CAPEX in the next three years. If we extend the methodology from conventional to porous wafers and upgrade from the existing equipment, the cost saving on CAPEX can be over £4M.
Time-resolved spectroscopic and microscopic measurements of multiple quantum well (MQW) on porous GaN wafer
Porotech is an emerging Gallium Nitride (GaN) material technology developer and a spin-out from the University of Cambridge. We develop commercial-quality epi-wafers using innovative porosification technology, enabling our customers to unleash the potential of GaN electronics and optoelectronics. By introducing nano-pores (10-50 nm) into epitaxial film (50nm-5µm) at wafer-scale (6, 8, 12 inches), the whole wafer's optical, mechanical, thermal and electrical properties become tuneable. In Nov 2020, Porotech launched the disruptive Native Red Epi-wafer (Red emission from InGaN-based epi-structure) for microLED applications. In May 2022, Porotech launched full colour MicroLED displays with DynamicPixelTuning (DPT) Technology, enabling a pixel's emission to be tune to any wavelength in the visible range using a simple drive scheme. So our platform technology based on porous GaN not only red-shifts the InGaN LED's emission, but also can dynamically tune its colours from red to blue.
Through this project we will establish the correlation between the colour tuneability and microstructures in MQW LED built on porous wafers. This will accelerate development progress for more efficient microLED products, resulting in lower cost, reduced risk, and much higher manufacturing yield.
This knowledge will be transformed into Porotech's competitive advantage over those companies that do not invest in fundamental understanding, and hence potentially afford us leadership in microLED market share. Our aim is to supply porous wafer materials for microLED with dominant advantages. By our collaboration, we believe NPL and Porotech will contribute significantly to the national economy, especially within the deep-tech sector.
Piezoelectric measurement of multiple quantum well (MQW) on porous GaN wafer
MicroLED, especially RGB microLED is considered as the holy grail of the future display technology. Porotech's mission is to bring microLED into commercial market at mass production scale through continuous innovation. Our microLED products based on unique process and customised porous structure have established advantageous position by achieving exciting technological and commercial breakthroughs in the past two years. However, until now, achieving the necessary high-efficiency, ultra-fine-pitch red pixels has proved a challenge for the whole industry.
Porotech fully acknowledge and understand the role that science has in aiding economic growth and add value to society. Evangelized by Dr Yingjun Liu, co-founder and CTO, Porotech's team will partner with NPL's Electronic & Magnetic Materials Team led by Dr Sebastian Wood, and Quantum Materials and Sensors Team led by Prof Ling Hao to meet the challenge through A4I program. The consortium is well equipped with bespoke facilities such as advanced scanning probe microscopy and non-contact microwave resonator system, aiming to establish multiple dimensional, multiple-scale view of hierarchical structure and complex spatial-temporal behaviours at device level in LED-on-porous-template. By the end of this project, we aim to establish a metrological methodology based on fundamental understanding, and ultimately meet manufacturing requirements to develop, optimise and assure quality of our wafer products.
Porotech has worked closely with NPL before. In 2020, via M4R Porotech worked with Rob Simpson from NPL for thermal measurement of porous wafer, which lead to deeper understanding of the thermal behaviours helping us to continue R&D even during pandemics. Our current collaborative project can lead to innovative solution on bigger challenges in the future on microLED, AR, power electronics, and quantum technology.
Porous InGaN for Red LEDs (PIRL)