Growth of GaN by microwave plasma enhanced MOCVD

Thin films of GaN on SI-GaAs and SnO₂ substrates were successfully grown by Microwave Plasma enhanced MOCVD at substrate temperatures in the vicinity of 650°C. These temperatures are substantially lower than the growth temperature of GaN using a conventional MOCVD, which is in excess of 1000°C. Trimethylgallium and nitrogen were used as precursors. A plasma applicator was used to create the nitrogen plasma, which was delivered from the cavity to the place near the substrate hearer using a quartz tube. X-ray diffraction measurements were revealed that the grown layer is a hexagonal structure. A Hall-van der Pauw technique was employed to measure the electrical properties. As grown material, room temperature resistivity, mobility, and carrier concentration are 36 Ω·cm, 73 cm²/V·s, and 4.6×10¹⁵ cm^-3 respectively. Photoluminescence measurements were performed using a He-Cd laser emitting at 325 nm at different the temperatures. Luminescence, centered at 2.9 eV were clearly observed. Meanwhile the UV absorption spectrum showed a band-gap of around 3.4 eV