Reliability Research Of Blu-ray GaN LD

Among the third generation semiconductor materials,GaN has many excellent properties as wide bandgap semiconductor,which can be used to prepare blu-ray GaN LD that has high quantum efficiency and excellent photoelectric properties.In recent years,the blu-ray GaN LD has a better application more and more widely in data storage,laser display and laser illumination,so it become a research focus in the field of semiconductor lasers gradually.For blu-ray GaN LD,with the growth of demand and the maturity of the market in wide application gradually,the reliability of device has become the most important factor which limit its development.It is a complicated and arduous process to study the reliability of blu-ray GaN LD,which has very requirements for experimental instruments and environment,therefore,there is no mature conclusion at home and abroad about the detailed mechanism of the reliability for the moment.At present,the understanding of the factors that affect the reliability of blu-ray GaN LD is focused on theoretical aspects mainly,which includes the proliferation and diffusion of dislocation and defect in active region,the degenerative damage of the cavity surface and the degradation of ohmic contact,the above changes will lead to the deterioration of LD's photoelectric properties and cause the ultimate failure.In this project,it is studied in a more detailed way with the combination of theory and experiment about the reliability of blu-ray GaN LD,and the specific research work is summarized as follows:1.This paper investigates the development and application of blu-ray GaN LD,and it is found that the most important factor of hindering the development of blu-ray GaN LD is the reliability cannot meet the requirements of practical application.Besides,aiming at the reliability research of blu-ray GaN LD,this paper also has a depth investigation of research status at home and abroad.2.It is described in detail about the working principle,epitaxial growth and chip fabrication of blu-ray GaN LD in this paper,meanwhile exploring the degradation mechanism and the stress conditions that inducing degradation of blue GaN LD deeply and analyzing the specific impact on reliability.In addition,this paper also analyzes the failure modes and accelerated aging under overstress conditions of blu-ray GaN LD.3.The epitaxial wafer of blu-ray GaN LD was tested and analyzed to determine the epitaxial quality and its possible effect on the photoelectric properties of blu-ray GaN LD.In addition,that were detected and analyzed the external appearance and the internal material in micro area in order to understand the epitaxial condition and chip characteristics of blu-ray GaN LD further after the completion of chip fabrication.After that,it was tested that the photoelectric properties of blu-ray GaN LD to obtain the characteristic parameters before aging.4.The aging of blu-ray GaN LD was carried out and observing the life under high current stress and analyzing the power attenuation in the aging process.The photoluminescence characteristics of the aged blu-ray GaN LD were tested again to determine the specific degradation caused by the continuous stress during aging,and analyzing the root cause of degradation based on various degradation characteristics.Finally,it was detected and analyzed that the body changes of the blu-ray GaN LD in order to further determine that the main reason for weakening its reliability was the increase of leakage current and loss,the decrease of carrier injection efficiency and the decrease of refractive index of the active area,which were caused by the degenerative damage of front cavity surface,Indium cluster in active area,burn out in ridge region,propagation of dislocation and so on.