Active nitrogen flux measurement during GaN growth based on the transmitted signal detected with a pyrometer

A novel approach for the measurement of the Nitrogen active species generated by a plasma source in the molecular beam epitaxy environment is here presented. The method is based on the analysis of the variations in the optical signal measured by a pyrometer during a two step, Gallium rich and Nitrogen controlled, growth modes. The method permits a precise, quantitative and direct measurement of the flux of active species as a function of the plasma generation parameters of the cell: nitrogen gas flux and RF-power.