Ultrathin barrier AlN/GaN high electron mobility transistors grown at a dramatically reduced growth temperature by pulsed metal organic chemical vapor deposition
Ultrathin-barrier AlN/GaN heterostructures were grown on sapphire substrates by pulsed metal organic chemical vapor deposition (PMOCVD) using indium as a surfactant at a dramatically reduced growth temperature of 830 °C. Upon optimization of growth parameters, an electron mobility of 1398 cm{sup 2}/V s together with a two-dimensional-electron-gas density of 1.3 × 10{sup 13 }cm{sup −2} was obtained for a 4 nm thick AlN barrier. The grown structures featured well-ordered parallel atomic steps with a root-mean-square roughness of 0.15 nm in a 5 × 5 μm{sup 2} area revealed by atomic-force-microscopic image. Finally, the potential of such structures for device application was demonstrated by fabricating and testing under dc operation AlN/GaN high-electron-mobility transistors. These results indicate that this low temperature PMOCVD growth technique is promising for the fabrication of GaN-based electronic devices.