Preparation method of p-type gan layer and led epitaxial structure

Abstract

The invention discloses a P-type GaN layer preparation method comprising the following steps: providing a substrate, putting the substrate in a reaction chamber, and keeping the temperature inside the reaction chamber between 650 to 800 DEG C; feeding an N source of which the partial pressure of NH3 accounts for 10-30% into the reaction chamber, and feeding an excess MO source until the surplus MO source is adsorbed on the surface of the substrate, wherein the MO source includes a Ga source and a Mg source; keeping the MO source closed, increasing the proportion of the partial pressure of NH3 in the N source to 30-70%, and making the N source react with the surplus MO source adsorbed on the surface of the substrate to grow a P-type GaN layer; and keeping the MO source and the N source closed, keeping N2 atmosphere in the reaction chamber for 10-30 seconds, and activating Mg in the annealing process. The invention further discloses an LED epitaxial structure preparation method. The P-type GaN layer is prepared in a low-temperature growth mode through intermittent MO source feeding and NH3 circulation between high partial pressure and low partial pressure. The concentration of holes in the P-type GaN layer is greatly improved, and the activation efficiency of Mg is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor light emitting devices, in particular to a method for preparing a P-type GaN layer and an LED epitaxial structure. Background technique [0002] GaN material has the characteristics of wide bandgap (Eg=3.39eV), high luminous efficiency, and long life. It has become the most preferred material for preparing blue and white light-emitting diodes (LEDs), and is known as the third-generation semiconductor material. Due to the large difference in lattice constant and thermal expansion coefficient between GaN and the substrate material (for example, the lattice constant difference between GaN and sapphire substrate is 16%), the dislocation density in the GaN epitaxial film is very large, usually 10 8 ~10 10 cm -2 , the room temperature background carrier (electron) concentration of undoped GaN material is as high as 10 17 cm -3 , showing n-type conductivity, doping Si can easily obtain n-type, ...

AI Technical Summary

Problems solved by technology

The generation of nitrogen vacancies will make the intrinsic GaN bias towards n-type, which is not conducive to the increase of hole concentration.

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