Development of gallium nitride MOSFET growth and processing technology

In an effort to further the progress of GaN metal oxide semiconductor field effect transistor (MOSFET) technology, some of the major challenges that it faces are addressed. The lack of a capable dielectric is one of the main obstacles to its advancement. One of the potential candidate dielectrics that has been previously looked at is scandium oxide (Sc2O 3). The epitaxial growth of Sc2O3 on GaN is thoroughly examined. Extensive characterization on the structural properties of the Sc 2O3/GaN material system was performed. Detailed analysis of the characterization results is presented and the thermodynamic and kinetic principles involved are discussed. The characterization analysis was performed in such a manner that makes it applicable to fcc-based cubic oxides, in general. The majority of the candidate dielectrics now being examined for GaN MOS applications are fcc-based cubic oxides, which makes this analysis a valuable tool in assessing the potential of many of these oxide/GaN material systems. The dominant growth technique for GaN production is metal organic chemical vapor deposition (MOCVD). The thermal and chemical stability in a GaN MOCVD environment of some of the potential dielectric oxides is investigated with respect to their structural and electrical properties. The p-n junction is typically the fundamental building block of electronic semiconductor devices. The fabrication of a good p-n junction for p-MOS devices is another obstacle in the development of GaN MOSFET technology. An alternative fabrication technique is explored that uses the MOCVD regrowth of heavily doped p-type GaN to produce the source and drain regions for a p-MOSFET device. The fundamental principles involved in the regrowth of GaN is considered and discussed. The development of lithography and chemical etching techniques for the fabrication of GaN-based MOS devices is integral to the advancement of GaN MOSFET technology as a whole. The ability of potential dielectric oxides to endure these processing steps is a fundamental requirement for the realization of GaN MOSFET technology. Based on the previous work done in this study, processing sequences for device fabrication are developed and the main issues involved their design are discussed.