Control, Characterization, and Modeling of GaN Low Temperature Growth

Device structures fabricated in III-V materials such as gallium nitride (GaN)require either deliberately induced defects to take advantage of ultra shortlifetime effects or ideal defect free crystallinity grown at low temperatureto reduce diffusion of hetero-junction interfaces.The essence of the proposed project is to use MBE crystal growth assistancetechniques, such as surfactants or in-situ external fields, to controlthe defectivity or crystallinity of a test vehicle compound semiconductor, suchas GaN, which shows promising characteristics for both military and civilianuses. A test device will then be fabricated to demonstrate the differentelectrical behaviors of the grown semiconductors.In order to reduce the number of iterations before arriving at a particularrecipe, it is desirable to model the crystal growth kinetics using software.To summarize, therefore, the total project is split into three main areas:- (i) software modeling techniques to reduce the experimental map. (ii) experimental MBE growth assistance techniques, such as surfactants or locally applied electric fields. (iii) creation of an electrical test vehicle such as a light emitting diode (LED) to investigate electrical quality of the grown layers. The benefits of this program will be the improved control over the crystal growth of GaN and hence the ability to accurately control the growth of defects if required. In order to reduce the total design of experiments it is also proposed that the crystalgrowth kinetics be modeled accurately using software yet to be developed. The commercial market for GaN runs into the billions of dollars but the material will not reach it's potential until the manufacturing issues are resolved. There would be two majorbenefits from our work.1. A technique of controlling the ions during MBE to eliminate random defects2. The ability to simulate the crystal growth kinetics to reduce the number of physical experiments required to find optimal growth conditions.