The proposed research will demonstrate the feasibility of a direct plasma-liquid process for bulk synthesis of polycrystalline Group III nitrides. In comparison with thermal chemical reactors, plasma assisted deposition systems have the advantages of cleaner reaction environments, and higher product purity. Recent developments at Case Western Reserve University (CWRU) have shown that the Group III nitrides can be grown by direct reaction using a microwave electron cyclotron resonance (ECR) plasma source. The innovation proposed is to use a microwave plasma at higher operating pressures and higher nitrogen throughput. These conditions will allow us to overcome transport limitations of the ECR system and convert a larger percentage of the liquid metal substrate. The system will also allow for higher thermal energy transfer to the substrate and, therefore, greater efficiency. Our technical objectives are to grow GaN and Al of high crystalline quality and purity. Various process modifications will be made to enhance the transport of reactive nitrogen to the unreacted metal. We will identify the best conditions for nitride growth. Once growth of the nitrides is demonstrated (Phase I), a commercial scale system will be designed that will make the process semi-continuous. This design will minimize capital costs while maxi zing conversion and energy efficiency. In Phase II the commercial scale system will be built and tested. With these modifications, we will develop a cost effective method for growing high quality group III nitrides. The high quality bulk, polycrystalline Group III nitrides grown will be used as source materials for single crystal growth and as device materials. GaN and its alloys could be sublimed (or ablated) to form thin film light emitting diodes, field effect transistors and diode laser structures. High quality polycrystalline GaN can be used for W detectors, inexpensive LED's and as seed material for single crystal growth. There is also great demand for high purity A N powder for the fabrication of high thermal conductivity electronic substrates. In markets such as telecommunications and radar, the highest crystalline quality, lowest impurity level substrates for thermal management are required
