Inventors: Dr. Simon Fairclough & Professor Rachel Oliver, Cambridge Centre for Gallium Nitride
Multi-layer semiconductor devices are the heart of the modern electronics industry and are constantly being developed to produce ever more energy efficient and smaller devices. The inventors are world-leading experts on Gallium Nitride (GaN), and have already created a spin-out company Porotech which is using Gallium Nitride to develop MicroLED (µLED) displays as well as solutions for power management, lasers and quantum light sources.
Multi-layer semiconductor wafers face challenges to manufacture at scale, and current processes need to be refined each time a modification is made to an existing design. GaN as an example is grown on a support wafer based on sapphire, Silicon Carbide (SiC) or Silicon. Typically 50 or more wafers will be made in order to perfect the manufacturing process for a single design, taking as much as 24 months of development. As more layers are added the problem becomes even more complex – some research devices are already using 12+ layer structures. This is further complicated when making µLEDs, where for some manufacturing paradigms the support is etched away leaving a free standing GaN structure whose shape is profoundly affected by the process by which it was grown.
Commercially a key requirement is to produce completely flat wafers and µLEDs so that devices can be fabricated using existing well-developed optical lithography techniques and so that all electrical contacts remain intact and high quality.
The team have developed a software modelling tool that can calculate the strain and predict the curvature of multilayer GaN wafers as the wafers form in a reactor, and also the impact of this strain on µLEDs. The predictions of the software model have been tested successfully by measuring the strain and curvature of real wafers in the lab. The inventors are now looking to use this throughout the GaN industry to support the manufacture and commercialization of GaN-based products.
The challenge for the i-Team is to investigate which industries are looking into using GaN-based devices and recommend where the tool can add most value as well as the features that it will need to have. The i-Team will also look at possible approaches to making the tool available, for example as a consultancy service or as a standalone software modelling system.