Preparation And Performance Of The Metalized Ceramic Substrate For High-power Light Emitting Doxides (LED) Heat Dissipation

The heat in high-power LED that was not dissipated from chip to surroundingefficiently and quickly would seriously influence the emission spectrum, luminousintensity, packaging material reliability, chip life and so on, so it is necessary to studythe heat dissipation of high-power LED. AlN ceramic substrate one of the heatdissipation substrate will be widely used in high-power LED owing to its someadvantages, such as insulativity, chemical stability, thermal conductivity and thermalexpansion coefficient.We summarized the metaling method of AlN ceramic substrate, and chosedelectroless copper plating to carry out this study. And the performance of the proposedsubstrate was respectively detected by Scanning Electron Microscope (SEM), EnergyDispersive Spectrometer (EDS), X-ray diffraction (XRD), Coating adhesion scratchexperiment, electric conductivity testing and thermal conductivity testing. Secondly, theinfluence of annealing and activation for Cu coating on AlN ceramic substrate wereinvestigated. Finally, we used finite element model to analyze the electric-thermalproperity of the packaged LED on Al and AlN ceramic substrate, and compared with theexperimental results including infrary camera and thermal resistance testing. Weacquired some follow conclusions:①An amorphous, smooth and compact Cu coating was succeed in depositing onAlN ceramic substrate using electroless copper plating, and there do not exist oxidelayers between substrate and Cu coating, such as CuO or Cu2O.②The optimal parameters of the maximum adhesion force and electricconductivity were obtained by partial differential for response surface equation, andgiven as following: copper sulfate21.61g/L and19.57g/L, sodium potassium tartratetetrahydrate31.18g/L and38.76g/L, methanal26.32mL/L and29.84mL/L, pH=13.39and12.90, temperature45.61℃and35.87℃, and the optimal value were20.56N and2.71×106S/m, respectively. Finally, the optimal synthetic parameters were copper sulfate20g/L, sodium potassium tartrate tetrahydrate35g/L, methanal35mL/L, pH=13.0,temperature40℃, while adhesion force was18.45N, electric conductivity was2.65×106S/m，deposition rate was0.026g/s.cm2and thermal conductivity was147.29W/m K, respectively.③According to the investigation results of annealing and activation, we can obtain a better Cu coating under annealing300℃and activation25min.④The thermal resistance of Al and AlN ceramic substrate packaging GaN-LEDlamp was10.61℃/W and2.71℃/W, and the infrary testing temperature was77℃and63℃, respectively.⑤Comsol multiphysis of finite element model was used to simulation thetemperature and current density distribution of Al and AlN ceramic substrate packagingGaN-LED lamp, and the relative errors to experimental results was0.92%and0.60%.⑥Finite elements methods are used to investigate thermal-electricalcharacteristics of gallium-nitride (GaN) light-emitting diodes (LED) with differenttransparent conductive layers (TCLs) and electrodes buried depth, where transparentconductive layers include indium tin oxide(ITO), graphene(Gr) and the combination ofthem(ITO/Gr). The results indicate that LED with TCL of100nm ITO or4-layers Grhas a good thermal-electrical performance from the point of view of the maximumtemperature and the current density deviation of multiple quantum well (MQW). Thecompound TCL with20nm-ITO and3-layers Gr reaches to a better thermal-electricalperformance. The electrodes buried depth is0.51μm, the thermal-electrical performanceof the GaN-LED can be further improved.