Reproducible and Highly Uniform Growth of GaN by MOCVD and MBE
Mike Wojtowica1, Ben Heying1 Patrick Chen1, Ioulia Smorchkova1, Randy Sandh1 , Tom Block1, Mike Aumer2, Darren Thomson2, and Deborah Partlow2
Systems, MS EF/3B10,
The high breakdown voltage and good thermal conductivity of the AlGaN/GaN material system enable linear, high power and survivable, low noise solid-state amplifiers with good operating efficiencies. At the present time, device performance is limited primarily by materials issues, i.e. variability in the quality of the substrate and the epitaxial HEMP structure. The reproducibility of high quality epitaxial materials is key to system implementation of this promising technology.
At Northrop Grumman, we have demonstrated 2” – 3” epitaxial films on semi-insulating SiC substrates with <3% variability in critical film properties. The work entailed extensive study of the MBE and MOCVD growth processes and the relative importance of each variable, as well as the employment of techniques to control process parameters sufficiently for excellent film uniformity. Figure 1 illustrated our increasing control of the MBE grown epitaxial HEMT material as we have identified and improved the key growth variables.
We will discuss our growth capabilities, methods used to ensure reproducibility and uniformity, methods of mitigating critical material issues, and the relationships between material properties and device performance issues.