OPTIMIZATION OF ALGAN FILMS GROWN BY RF ATOMIC NITROGEN PLASMA USING IN-SITU CATHODOLUMINESCENCE

In-situ cathodoluminescence (CL) is presented as a technique for deter mining film composition, optical quality, doping levels, and temperatu re of MBE grown group III nitride films. Excitation of the films is do ne with either the Auger or RHEED electron gun operating between 1 and 10 keV. The CL emission is monitored using a 3 nm resolution monochro mator. Optimization of the GaN growth process using a RF atomic nitrog en plasma source is discussed using in-situ cathodoluminescence to red uce the ''yellow'' defect level present in GaN. Composition and qualit y of AlxGa1-xN films are shown to be quickly determined from the peak position and width. This is extremely useful in the nitride system whe re reflection high-energy electron diffraction (RHEED) oscillations ar e not routinely observed. Measurement of the substrate temperature dur ing GaN growth is demonstrated by monitoring the shift in band edge po sition with temperature. p-type doping and MQW levels observed by CL a re shown to allow quick optimization of device and material properties .