Improved gas utilization in GaN growth system

Important results from the project

The growth of the semiconductor material is controlled by how gas molecules that are added to the process chamber are decomposed and then the crystal builds up. The decomposition is controlled, among other things, by the temperature in the process chamber. There are various ways to increase the decomposition so that the amount of gas can be reduced while maintaining the growth rate.

Expected long term effects

The result shows that in some cases the amount of gas can be halved. Due to the very large number of variables that affect growth, growth has not been optimized. The chemical process steps are affected by the gas composition and thus the gas flow, temperature and geometric design must all be optimized and they are interrelated. Complete optimization has not been possible within the framework of the project. However, it is clear that a significant improvement can be made.

Approach and implementation

The experiments were carried out in a hot-wall reactor at Linköping University in collaboration with staff from SweGaN AB. Because it was difficult to get the desired reactor time, the tests have been limited to the most important tests. In the tests, different temperatures and gas flows have been tested. It has not been possible to test different geometric designs. Evaluation of the various experiments was primarily done by staff from SweGaN. The variables measured include growth rate, electrical properties such as mobility and charge carrier concentration and surface roughness.