Threading dislocations reduction of GaN-on-Si by introducing AlN/3D-GaN with SiN interlayer for photodetectors

Gallium nitride -on -Silicon epitaxy technology has enabled a high level of large-scale GaN integrated manufacturing. However, the poor crystalline quality of GaN on Si substrates dramatically deteriorates device performance. This work demonstrates the application of a buffer layer structure of AlN/3D-GaN with a SiN interlayer to obtain GaN films with high crystalline quality on Si substrates. Transmission electron microscopy and X-ray diffraction reveal reductions in GaN dislocation density. The full width at half maximum values of the X-ray rocking curve for the GaN(0002) and (10-12) planes have decreased from 499 to 710 arcsec to 339 and 350 arcsec, respectively. Ultraviolet photodetectors based on the optimized GaN-on-Si substrates exhibit low dark currents (34 pA@10 V) and high responsivity (6.8 A/W@10 V). Our reported novel buffer architecture provides an important reference for improving the performance of other GaN-based optoelectronics and power electronic devices on Si substrates.