| The growth of Mgδdoped AlGaN epitaxial films by MOCVD method was reported in this paper. The characterizations of crystalline quality, surface morphology, electrical properties and the concentration distribution of impurity atom of the grown samples were introduced in the paper.The following results were achieved for the samples grown by uniform Mgδdoped AlGaN:(1) the quality of films decreases with increasing annealing temperature;(2) the surface atoms will begin to escape when the annealing temperature is 900℃, at the temperatures below 800℃, thermal annealing is unable to provide enough energy to break Mg-H complex;(3)we obtained the best annealing temperature: 850℃and the best resistance of Mgδuniform doping Al0.25Ga0.75N at room temperature: 4.37Ωcm;(4)the annealing process not only causes the decomposition of Mg-H complex, but also contributes to the reduction of the O atom concentration, both of them are helpful to the enhanced performance of the p-type AlGaN.The samples with differentⅤ/Ⅲgrown by Mgδdoped method was made, and compared to the sample by uniform Mgδdoped, the following results were made:(1)comparing to the sample by uniform Mgδdoped, the samples by Mgδdoped can reduce the surface activity effectively, making the surface diffusion length of Al/Ga atoms longer and more prefer to two-dimensional growth, whose crystal quality and morphology are more perfect;(2)the method of Mgδdoped will reduce number of Mg-H complex effectively in the doped films, and reduce the activation energy of Mg, which will increasing the hole concentration and finally reduce the resisivity; (3) after analyzed, we obtained the optimalⅤ/Ⅲvalue: 3220 and the lowest resistivity at room temperature: 1.92Ωcm to the p-type Al0.25Ga0.75N by Mgδdoped method. |
PDF Full Text Request