Growth of Thick GaN Epitaxial Materials on 150mm Engineered Substrate

In this paper, we present the first demonstration of GaN epitaxial layers exceeding 12 μm in thickness, grown on engineered substrate (GaN-on-QST) within a domestic context. The results of our analysis reveal that the epitaxial wafer is crack-free, with a root-mean-square surface roughness of 0.224 nm, indicating a high level of surface smoothness. Additionally, the warpage (bow) of the sample is minimal, measuring only 6.086 μ m which is crucial for maintaining structural integrity in device applications. The full width at half maximum (FWHM) of the (002) and (102) crystal planes are 131 arcsec and 272 arcsec, respectively, suggesting a high degree of crystallographic orientation and order. Furthermore, the sheet resistance of the sample is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$276.5\ \Omega/\square$</tex> and the two-dimensional electron gas mobility (2DEG) is measured to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2150\ \text{cm}^{2}/(\mathrm{V}\cdot \mathrm{s})$</tex>, which are important parameters for evaluating the electrical properties. This work paves the way for growing even thicker GaN epitaxial layers on larger QST substrates and opens up new possibilities for future high-voltage GaN power electronic applications.