Effect Of Heat Treatment On The Quality Of Gallium Nitride Epilayers By MOCVD

GaN is wide band gap and direct-gap semiconductor material. It is broadly applied in the area of semiconductor devices. However, the develepment of GaN based devices is confined by the less of suitable substrate materials. So how to improve the quality of GaN epilayers is the important.In this paper, GaN epilayer was grown on sapphire substrate in Metal Organic Chemical Vapor Deposition (MOCVD) reactor. Rapid thermal processor and conventional heat treatment were introduced to study the effect of heat treatment on the properties of GaN epilayers.The results showed that the quality of the GaN epilayer was improved after heat treatment. The full-width at half- maximum (FWHM) of the GaN epilayer became narrow and the quality of the epilayer was improved along with the rise of annealed temperature and annealed time extended. The residual strain of the GaN epilayer heat-treated was released. The yellow-band intensity of the GaN epilayer without heat treatment is higher than that heat-treated. It shows the luminescence property was improved through heat treatment. The electrical performance of the GaN epilayer with heat treatment were compared with the GaN layer without heat-treated, the results showed that the electrical performance was improved after heat treatment. The carrier concentration of the sample which was rapid thermal processor by 950℃is 1×1018cm-3.