First real-time true wafer temperature and growth rate measurements in a closed-coupled showerhead MOVPE reactor during growth of InGa(AsP)

In this paper, we report on an optical in-situ study using a novel in-situ sensor to measure the true wafer temperature and reflectance in a Thomas Swan closed-coupled shower head reactor. Measurements have been performed during growth of InGaAs and InGaAsP on InP. By means of emissivity corrected pyrometry the true wafer temperature is directly accessible in real-time. Simultaneous reflectance measurements have been utilized for precise growth rate measurements. The measurements have been made in a wafer selective manner allowing run-to-run variations to be tracked, and comparisons between wafers to be made. The effect of changes in growth temperature, (e.g. due to different coatings of the susceptor, or after changing a susceptor), on the emission wavelength of the quaternary InGaAsP has been studied.