Growth And Characterization Of GaN Films Using MOCVD Method

Gallium Nitride (GaN) is an excellent chemical semiconductor material and also is one of the most advance semiconductors in the world. GaN has been regarded as one of the most promising materials for light emitting devices. Because is has a direct band gap of 3.4 eV at room temperature. In addition, GaN exhibits high thermal conductivity and little radiation damage, so it can be applied to high power and high temperature microelectronic devices. Due to the polar GaN films possessing the blueshift of photoluminescence and low radiative recombination, non-polarized GaN films have changed a new hot research. In this paper, we tentatively grew the non-polarized GaN films on sapphire substrates. This reaserch was a base of the future research such as the fabrication of devices, nanoporous GaN films and self-standing GaN films. The detailed content can be summarized as follows:Firstly, we grew the M-axis oriented GaN films on sapphire substrates at the different growth temperature. The results indicated that the quality of GaN films grown at 1050℃was the highest.Secondly, we synchronously changed the growth pressure of buffer layer and growth layer. The research found that the quality of GaN films grown at 5-10torr is the highest, and the growth rate of GaN film decreases as the pressure increasing.Thirdly, we changed the growth pressure of buffer layer and normal growth layer, respectively. The measurement results indicated that the high-quality GaN could be grown on the below growth condition. This is the buffer layer grown at the pressure of 5 torr for 2 min and the growth layer grown at the pressure of 10 torr.Lastly, in order to research the influence of buffer layer's temperature, we changed the growth temperature of buffer layer. The results found that the higher growth temperatures of buffer layer are better for the growth of GaN films.