Advancing semiconductor materials growth processes
The 'MOCVD technology for production of indium nitride based nanophotonic devices' (INDOT) project worked to develop a metal-organic chemical vapour deposition (MOCVD) technology for industrial production of indium nitride (InN) quantum dot (QD)-based devices. The EU-funded project envisioned that the know-how produced would also be applicable to the production of InN- and In-rich indium gallium nitride (InGaN) alloy-based devices. Development of new precursors suitable for growth of high-quality InN QD and In-rich InGaN layers focused on ensuring a reliable fabrication process and potential for the scale-up of specific procedures to production level. INDOT project partners developed three series of compounds for accessing lower growth temperatures, enhancing stoichiometry control and fully optimising accessible deposition parameters. Experimental processes were refined, revealing ultra-high purity materials yield in a reliable and scaleable fashion. The new combination of precursors suitable for InN-based device fabrication to the highest standard was thus ready for launching. Efforts to improve MOCVD equipment for the low-temperature growth of InN and InN-based compounds emphasised the realisation of optimisation through stable, reproducible and efficient processes. INDOT's main achievement in this area was making available MOCVD prototype equipment for research and development (R&D) as well as for industry. This can be used for the production of advanced InN- or In-rich InGaN-based devices, but is not limited to these materials. Using the new precursors and the optimised equipment, MOCVD processes have been developed for the deposition of InN QD and InGaN films at low temperatures, with the In-rich InGaN grown at moderate temperatures proving especially successful. Other INDOT achievements include obtaining extremely flat surfaces, which open the way to improving InN grain structure.