Thesis presented April 26, 2022

Abstract:
This thesis reports on the selective area metalorganic vapor phase epitaxy of InGaN/GaN multi-quantum wells for self-emissive micro-displays. GaN-based LEDs have been recognized to be very attractive for this application, thanks to their properties which include high brightness and efficiency allowing low power consumption and good reliability.
To date, one of the main challenges ahead for the micro-displays technology is the production of full color devices integrating RGB emitting pixels, with a pixel pitch below 10µm. This study aims to achieve wavelength modulation of InGaN/GaN multi-quantum wells using selective area growth (SAG). This technique consists in patterning the surface of a substrate with a dielectric amorphous mask. During growth, the gas species do not deposit on the mask, but migrate to the openings defined beforehand. InGaN wells with different thicknesses (from 1 to 9nm) can be obtained during the same growth run, resulting in different emission wavelengths from various regions on the wafers.
The study presented in this manuscript is based on the selective growth of nitride layers, their characterisation, and the numerical simulation of SAG effects based on vapor-phase diffusion and surface diffusion. In a first part, the selective growth of the binary compound GaN and the InGaN alloy is investigating as function of growth conditions.
Secondly, the influence of growth parameters and mask geometry on the properties of InGaN/GaN multiquantum wells is studied. This leads to the demonstration of an extended modulation of the emission wavelength measured by photoluminescence, from 405 to 608nm in growth area of 3 µm and obtained in a single localised growth run at 805 °C, allowing the possibility of applying this technique to the manufacture of emissive micro-displays.

Keywords:
MOVPE, GaN, Selective area growth, Multi-Quantum Wells, InGaN, LED

On-line thesis.