8-inch free-standing GaN substrates grown by hydride vapor phase epitaxy

Abstract The absence of large-size gallium nitride (GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off (LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of (002) and (102) planes, alongside a low dislocation density of 1.6 × 10 6 cm −2 . This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics.