Au/n-GaN Schottky diode grown on Si(111) by plasma assisted MOCVD

Most of the growth of GaN epilayers by MOCVD method reported to date was carried out at growth temperature above 1000°C on sapphire substrates. We have successfully grown GaN by plasma assisted MOCVD (PA-MOCVD) method at temperature between 560°C to 650°C. In this paper we report an attempt to fabricate Au/n-GaN Schottky diode grown on Si(111) by PA-MOCVD method. The GaN films were grown at temperatures of 625°C and 650°C using trimethylgallium (TMGa) and nitrogen plasma. The diode is a concentric type using aluminum as ohmic contact and gold as Schottky contact. Electrical characterizations were performed by I-V and C-V measurements. The barrier heights determined from I-V measurements are 0.44 eV and 0.49 eV, for Schottky diodes grown at 625°C and 650°C, respectively. The ideality factors are 4.5 and 5.6 indicate that tunneling as the main mechanism of electron transport through the barrier. This mechanism is typical for moderately to highly doped semiconductor, as confirmed from C-V measurement.