The DFM Of GaN-based Blue LEDs On SiC Substrates

In recent years, GaN materials and components have become a research hotspot, especially in GaN-based light emitting diode (LED). LED is energy saving and environment friendly light source. Because of its excellent characteristics, such as small volume, cold light source, high luminous efficiency, energy saving, long operating life, and so on, it can be used in all kinds of hostile environments.The paper first generalized the development history and actuality of SiC and GaN material, discussed the characteristics of SiC and GaN-based material, detailedly analyzed the structure and basic working principle of GaN-based Blue LEDs on SiC Substrates, especially the electronic characteristics and optical characteristics. According to the theoretical analysis, selected the suitable physical models. Focused on the process condition, such as SiC substrate structure size, well width of the Quantum-well, the mole fraction of In in InGaN alloy and the mole fraction of Al in AlGaN alloy. With the new TCAD tools SWB and PCM studio developed by Synopsys Inc., the research made a process and device simulation according to quantum efficiency of the device, current-voltage characteristics and optical power. Based on the method and theory of DOE and choose the suitable response surface model, the paper made a thorough study of the relationship between process parameters and characteristics of device. By optimizing parameters, we got the best process conditions finally. At last, the paper made a simple analysis on the results of DFM of GaN-based blue LEDs on SiC substrates combined with quantum effect, polarization effect, piezoelectric field effect and so on. Finally the structure size and process parameters were determined, the DFM of LED was finished.This research thoroughly discussed the process parameters and physical properties of GaN-based blue LEDs on SiC substrates, after the DFM, we got a LED with4periods quantum-wells and the width of substrate was225μm. The peak wavelength was470nm, the extraction efficiency was62.5%, the threshold voltage was3V and the forward voltage was3.35V. All of the parameters had met the design requirements, it laid a foundation to the research of LEDs on SiC substrates in China and had a certain reference value.