Abstract
Chemical vapor deposition (CVD); hydride vapor phase epitaxy (HVPE); gallium nitride (GaN); indium gallium nitride (InGaN); scandium nitride (ScN); scandium aluminum nitride (ScAlN); semiconductors; thin films; nanowires; III nitrides; crystal growth
- We studied the HVPE growth of different III nitride materials. For GaN the aim was creating thick high quality films as a basis for white light LEDs, Blu-ray lasers and high power transistors. We managed to increase the deposition rate of the GaN HVPE process by a factor of 5. Also the number of crystal defects improved a 1000 times and we managed to grow 4× thicker wafers within a single process. All this was achieved by replacing the commonly used HCl process gas for Cl¬2. Using Cl2 we also managed to create InGaN films, which can be utilized to create LEDs of any color, depending on the indium content.
Using classic HCl-based HVPE we were able to grow thin films of ScN, a scarcely studied semiconductor with great potential for a.o. solar cell applications. As a fortunate side product of this work, we created ScAlN, a novel combination of III nitrides, in the form of nanowires.
Finally, we achieved a better understanding of the fundamentals of the HVPE GaN process. We learned how exactly the GaN growth starts on a foreign sapphire substrate and how this process helps eliminate defects in the GaN crystalline film. Looking towards the future, we wrote a basic set of rules for scaling up the HVPE process to industrial sizes, which we verified by computer simulations.
