Influence Of Different Support Submounts On Stress And Luminescence Properties Of The GaN-based LED Film

Ga N-based LED has been widely used in the lighting field and closely linked with people’s lives, but the improvement of the existing production process, the development of new technologies, the related physical mechanism research is the hot spot in the whole field. At present, the commercialization of Ga N based LED Epitaxial substrate is divided to three technical routes which are silicon carbide(Si C),sapphire(Al2O3) and silicon(Si) substrate..Although silicon substrate Ga N- based LED took the lead to realize the industrial production in China, and became one of three main semiconductor illumination technology routes, but it still has a lot of unsolved problems in science and technology and is worth in-depth research by multidisciplinary cross-integration. Whatever is the epitaxial Ga N substrate, after stripping it is transferred to the new substrate and made high-power devices with vertical structure which is necessary for realization of semiconductor lighting. The research on the effects of all kinds of stress for optical and electrical properties in the process of Ga N- based LED epitaxial growth,manufacturing chip, packaging devices and using LED is a hot spot in current research, the research of this phenomenon in the literature mainly focus on the lateral structure the Ga N epitaxial substrate from stripping, however the research of all kinds of stress for vertical structure of Ga N-based LED devices especially on silicon substrate Ga N-based LED device is still in the initial stage. Based on silicon substrate Ga N-based LED platform, this paper design and prepare a variety of different vertical structure Ga N-based LED and LED films on different stress state, to study the relationship between stress and LED photoelectric properties and by high resolution X ray diffraction(HRXRD) analyze internal stress and quantum wells of LED films under different stress conditions. The research results obtained:1) Epitaxial growth of gallium nitride(Ga N) based light emitting diode(LED)film on Silicon(Si) substrate is transferred to the substrate containing flexible adhesive layer, obtaines LED thin films without being constrainted by substrate and support substrate. Take advantage of the High-resolution X-ray diffraction scanner(HRXRD) to study the shift stress variation of the thin film before and after it being transferred, at the same time the photoluminescence(PL) spectra properties were studied. The results show that: After Ga N-based LED film on the silicon substrate istransferred to the flexible substrate, huge of tensile stress of Ga N before being transferred becomes the small pressure stress after being transferred and compressive stress from In Ga N/Ga N quantum well increases; despite after LED thin film at room temperature losslessly transferred to flexible substrate, In component of the In Ga N well layer will not change, according to general calculation method of reciprocal space mapping(HRXRD),obtaine a Conclusion:average Indium component changes;its PL spectrum can have the obvious red shift after Ga N-based LED thin film from epitaxial wafer to flexible substrates.2) Epitaxial growth of gallium nitride(Ga N) based light emitting diode(LED)film on Silicon(Si) substrate is stripped and transferred to new silicon substrate and copper substrate and access to the LED chip with the vertical structure,as well as electroluminescence(EL) characteristics of the variable temperature and current were studied. The results show that: when the environmental temperature is constant, the wavelength of EL with the chips of copper substrate under low temperature(13K) is always higher about 6nm than chips of silicon substrate, when the temperature is300 K, with the driving current increasing, the wavelength of EL with the chips of copper substrate is always higher about 3nm than chips of silicon substrate and and gradually becomes to coincide with the silicon chip; When the drive current is constant,or the ambient temperature increased from 13 K to 320 K, the peak wavelength of EL chips of two substrates showed “S” cureve with temperature increasing and spectral tended to overlap; Below 100 K droop effect with chips of copper substrate is more obvious than chips of silicon substrate, whether above 100 K the droop effect with chips of the silicon substrate is more obvious than chips of the copper substrate. Maybe two kinds of chips based on substrates has different thermal expansion coefficient and thermal conductivity,which has led to the different electroluminescence(EL) characteristics under the variable temperature and current.