Influences of periodic Si delta-doping on the characteristics of n-GaN grown on Si (111) substrate

• Si periodic δ-doped GaN and Si uniformly doped GaN with varying doping levels grown on Si(111) substrate were compared.
• The tensile stress in GaN:Si was significantly reduced with periodic δ-doping.
• Superior electrical properties were achieved in the Si periodic δ-doped GaN films without cracks.
• XRD measurements demonstrated equivalent crystalline qualities of the GaN:Si layers through the two doping methods.

We investigated the influences of periodic Si δ-doping on the characteristics of n-GaN grown on Si (111) substrate by metal organic chemical vapor deposition (MOCVD). By using periodic δ-doping, the tensile stress in GaN film induced by Si-doping was reduced to 0.057 GPa/1018 cm−3 electrons, which was 56% smaller than that in uniformly doped GaN. Moreover, superior electrical properties were achieved in periodic δ-doped GaN films without cracks by varying the Si doping level. X-ray diffraction measurements show similar 002 and 102 full widths at half maximum (FWHMs) for periodic δ-doped GaN and uniformly doped GaN with the same Si doping amount, implying equivalent crystalline qualities of GaN:Si through the two doping methods. A narrower FWHM of the near band edge emission of GaN was obtained in the photoluminescence spectrum with periodic δ-doping, indicating enhanced optical properties.