Capacitance-voltage characterization of AlN/GaN metal-insulator-semiconductor structures grown on sapphire substrate by metalorganic chemical vapor deposition

Electrical characterization of AlN/GaN interfaces was carried out by the ca pacitance-voltage (C-V) technique in materials grown by metalorganic chemic al vapor deposition. The high-frequency C-V characteristics showed clear de ep-depletion behavior at room temperature, and the doping density derived f rom the slope of 1/C-2 plots under the deep depletion condition agreed well with the growth design parameters. A low value of interface state density D-it of 1x10(11) cm(-2) eV(-1) or less around the energy position of E-c-0. 8 eV was demonstrated, in agreement with an average D-it value estimated fr om photoassisted C-V characteristics. (C) 2000 American Institute of Physic s. [S0021-8979(00)09313-0].