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Schlagwörter:
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Zusammenfassung:
Growth conditions have a tremendous impact on the unintentional
background impurity concentration in gallium nitride (GaN) synthesized
by molecular beam epitaxy and its resulting chemical and physical
properties. In particular for oxygen identified as the dominant
background impurity we demonstrate that under optimized growth
stoichiometry the growth temperature is the key parameter to control its
incorporation and that an increase by 55 degrees C leads to an oxygen
reduction by one order of magnitude. Quantitatively this reduction and
the resulting optical and electrical properties are analyzed by
secondary ion mass spectroscopy, photoluminescence, capacitance versus
voltage measurements, low temperature magneto-transport and parasitic
current paths in lateral transistor test structures based on
two-dimensional electron gases. At a growth temperature of 665 degrees C
the residual charge carrier concentration is decreased to below 10(15)
cm(-3), resulting in insulating behavior and thus making the material
suitable for beyond state-of-the-art device applications.
