Uniformity control of 3 inch GaN/InGaN layers grown in Planetary Reactors®

We present results obtained from a 2400G3HT reactor with a maximum wafer capacity of 8×3 inch. To achieve uniformity of the growth, we increased the temperature uniformity on each satellite to 0.9°C and that from satellite to satellite to 0.8°C. The optimum reactor geometry has been found by extensive modeling of the reactor design. Thus, an optimization of uniformity and efficiency has been achieved. GaN, InGaN/GaN multi quantum wells, GaN:Si, GaN:Mg and AlGaN were obtained on 5×3 inch substrates by simple scaling of the corresponding process parameters of the 6×2 inch configuration. We demonstrate GaN:Si and GaN:Mg doping uniformity with a standard deviation of less than 5%, with thickness uniformities of less than 1.7% standard deviation without any edge exclusion. InGaN/GaN, quantum well emission at 480 nm shows a standard deviation of 1–2% without rim exclusion. We grew AlGaN with about 10% Al content and less than 2% standard deviation in Al composition across the 3 inch substrate. Simple electroluminescence test structures, consisting of a GaN:Si buffer, followed by a five-period InGaN/GaN quantum well and covered by a GaN:Mg cap with emission wavelengths of about 460 nm show wavelength variations across 3 inch wafers of less than 3 nm. All these results demonstrate that the AIXTRON Planetary Reactor® is a very flexible tool for mass production application, especially with respect to upgrading the system to larger wafer diameters, as is already well known from the standard GaAs and InP applications that are available up to 5×8 inch configurations.