AbstractIn this thesis, stages of the manufacture of vertical indium gallium nitride gallium nitride on silicon light emitting diodes are investigated using both simulation techniques and physical experiment. These stages are the formation of a reflective contact to p-type gallium nitride, the use of nickel in wafer-level bonding, the use of the mesa etch to singulate micron-scale devices, and the use of both potassium hydroxide roughening on N-face gallium nitride and photolithographically patterned structures for light extraction. Furthermore, the methods of manufacture developed within these stages for generic lighting light emitting diodes are then applied to the manufacture of gallium nitride on silicon light emitting diodes with active area diameters of below 10μm. One common goal ties the development work in this thesis together, and that is the improvement of wallplug efficiency- in other words the amount of power emitted by the device compared to the amount of power required to run it.
The improvements in light emitting diode wallplug efficiency and reduction in cost achieved by use of the work in this thesis mean that more efficient light emitting diodes can be made and sold more cheaply, making them more attractive to consumers and reducing overall energy consumption for lighting.
The adaptations of the manufacturing process to accommodate the manufacture of light emitting diodes with active area diameters of below 10μm open the possibility of manufacture of gallium nitride on silicon based microdisplays for use in virtual and augmented reality headsets, applications with the potential for great societal benefit.
|Date of Award
|17 Jul 2019
|Philip Shields (Supervisor) & Duncan Allsopp (Supervisor)