The processing and characteristics of InGaN/AlGaN double heterojunction (DH) structure and of GaN epilayer grown on the α-Al

2

O

3

substrate by means of metalorganic chemical vapor deposition (MOCVD) technique are reviewed. The important effect of the MOCVD growth condition (temperature

gas source flow etc.) of the GaN buffer layer on the surface morphology

crystallinity and opto electronic properties is discussed from the point of view of the surface dynamics. The analysis indicates that the growth rate of GaN film is dependent chiefly on the furnace temperature

the molar flow rate of the gas sources. As increasing the temperature

the PL peak shifts to longer wavelength. The growth temperature of the GaN buffer layer must be controlled at 550℃. The high ratio of Ⅴ/Ⅲ gas source flows can restrain the radiant intensity about 550 nm in the GaN photoluminescence spectrum. To obtain a good epilayer film with high radiation rate the Cp

2

Mg source is used as the Mg acceptors doping in p-AlGaN and p-GaN compound semiconductor. It is noticed that

the epitaxial temperature and time

Mg doping dose should be optimally controlled

furthermore

the sample is annealed rapidly at 800℃ under the N

2

gas flow. In fact

above mentioned efforts have been made importantly on the lattice microstructure improvement and the increase of luminous intensity for the InGaN/AlGaN DH LED.