Subproject 3



Development of special high pressure and high temperature equipment, spectroscopic in situ investigations and fluid dynamics simulation


This sub-project is focused on the development of substance identification processes (e. g. measurement of the solubility of nitrides in the autoclave via spectroscopic methods (UV-Vis)) and on the definite identification of all possible educts, as binary and ternary compounds or even as compounds of higher order with optical methods. The development of liner materials and processes to attain the purity requirements of the semiconductor manufacturing and the extension of the existing sensor technologies is a further aim of this project in cooperation with sub-project Z and sub-project 6. Moreover the fabrication of prototypes of special reactor types, e. g. a reactor for the sampling and the realization of an optimal process regulation shall be carried out. By combining the analysis methods with other sub-projects we want to generate a broad knowledge regarding the solution processes and the reaction mechanisms. It is also planned to develop instruments and procedures, which allow the measurement of various substance parameters under real reaction conditions.

To reach the overall aim, the interaction within the group is essential. A close cooperation with sub-project 4 for the sampling under real conditions, with sub-project Z for the development of the instrumentation and with sub-project 6 for development of equipment with high purity requirements and the determination of temperature fields is intended.

The planning and fabrication of special reactors for the several sub-projects is also a topic of this sub-project. Special prototypes will be manufactured either in the mechanical workshop at the institute or procured from external sources. In the case of external procurement, we will plan and supervise the manufacturing process.

The results of the in situ investigations in combination with sub-projects 4 and 6 and the chemical analysis of the phases (sub-project 2) as well as the compounds (sub-project 1) will deliver an overall picture regarding the processes occurring inside the reactor.

With regards to the second stage of the project, the optical cell is planned for the use of high-speed recordings and laser-doppler anemometry to gain an insight into the fluid dynamics inside the cell for the first time ever. Since e.g. GaN-particles are hardly soluble in supercritical ammonia without additives, it is possible to use these particles directly as tracers. With the in situ measurements we also aim at the optimization of the mineralizers regarding the process temperature. Based on the results of the prototypes, developed in the first stage of the project for the determination of the material properties, we should be able to lay the foundations for reliable simulations. Based on the knowledge gained from the fluid dynamics and temperature field measurements verifiable CFD-simulations are possible. These results are of great importance for the development of a safe scale-up in sub-project Z.