On the Role of AlN Insertion Layer in Stress Control of GaN on 150-mm Si (111) Substrate

In this study, low-temperature (LT) and high-temperature (HT) AlN insertion layers (ILs) grown at 680 and 970 degrees C were integrated with 3.7-mu m GaN-based heterostructure grown on 150-mm Si (111) substrates by metalorganic chemical vapor deposition. Under a V/III flow ratio of 1960, the GaN epilayer with a continuous interface resulting from the LT AlN IL was subject to a compressive stress of -0.109 GPa. However, the GaN epilayer with discontinuous interfaces resulting from the HT AlN IL growth under the same flow ratio was subject to a tensile stress of 0.174 GPa. To realize continuous interfaces between the GaN epilayer and HT AlN IL, a higher V/III ratio of 5960 was utilized to suppress the decomposition of GaN. It results in changing the stress state of the GaN-based heterostructure from tensile to compressive. This strategic finding indicates that a stress-controllable GaN on Si can be achieved via the incorporation of HT AlN ILs. A minimum curvature at 5 km(-1) is demonstrated for the 3.7-mu m GaN-based heterostructure on a 150-mm Si (111) substrate, which has high potential for power switching device applications.