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Matthew's Project Page - RISE summer 2004 |
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Intern: Matthew Stabile, UCSB
Mentor: Benjamin Haskell
Faculty Supervisor: Shuji Nakamura
Department: Materials |
GROWTH OF LOW-DEFECT DENSITY NONPOLAR GALLIUM NITRIDE
BY HYDRIDE VAPOR PHASE EPITAXY
Nonpolar (1100) m-plane gallium nitride has been found to grow
heteroepitaxially on (100) γ-LiAlO2 by several groups. When grown by hydride
vapor phase epitaxy (HVPE), previous attempts yielded gallium nitride films that
were unsuitable for device regrowth due to unreasonably high defect densities on
the surfaces. Our growth of nonpolar gallium nitride films on (100) γ-LiAlO2 by
HVPE has eliminated these bulk and surface defects and produced a smooth enough
surface morphology to allow for the fabrication of m-plane gallium nitride
templates and free-standing substrates for subsequent nonpolar device regrowth.
With the production of useful gallium nitride wafers now feasible, a more
efficient HVPE crystal growth system must be implemented to allow an increase in
wafer production. The new HVPE system will be computer-controlled by a monitoring
and data acquisition program written on National Instrumentsˇ¦ Labview 7.0. The
program that I am designing will allow manual operation of the system, but most
importantly will include automatic control scripts that will monitor the system
state by continuously checking the status of various valves, pressure sensors,
and thermocouples. The system will be kept stable through specified alarm and
interlock conditions and will include an interpreter program for logging and
analyzing growth data.
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