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A low temperature growth method based on electron cyclotron resonance plasma-enhanced metal organic chemical vapor deposition system (ECR-PEMOCVD) was proposed for the growth of gallium nitride (GaN) films on ordinary soda-lime glass substrates with sputtered Cu as intermediate layer (Cu/glass substrates). The influence of deposition temperature on the properties of the GaN films on Cu/glass substrates was systematically investigated by means of In-situ reflection high energy electron diffraction, X-ray diffraction, atomic force microscopy and photoluminescence spectra. With this method, high c-orientated crystalline GaN films with relatively smooth surface were achieved on amorphous Cu/glass substrate at an extremely low temperature of ~400 °C. The successfully growth of crystalline GaN films on amorphous Cu/glass substrates show great potential for significant improvements in the scalability and cost of GaN based devices, since the adverse effects with high temperature process for glass substrates can be effectively suppressed by this technique.

Gallium nitride (GaN) films were deposited on Ni metal substrate using electron cyclotron resonance plasma-enhanced metal organic chemical vapor deposition system. With this approach, highly c-oriented GaN films with smooth surface were obtained at an extremely low temperature of ~480 °C. The trimethyl gallium (TMGa) flux dependent structural, morphological, and optical characteristics of GaN films were investigated by X-ray diffraction analysis, reflection high energy electron diffraction, atomic force microscopy and photoluminescence analysis. The results indicate that it is feasible to deposit GaN films on Ni metal substrate under the proper deposition procedures. The high quality GaN films with high c-axis orientation and strong ultraviolet emission peak are successfully achieved under the optimized TMGa flux of 1.2 sccm. The GaN/Ni structure has great potential for the development of high power devices with excellent heat dissipation.

Au-20 wt% Sn eutectic solder is used as bumps in flip chip package of power LED (Light Emitting Diode) due to its excellent properties. The Au/Sn dual-layer films were fabricated on Si wafer by pulse electroplating of Au and Sn sequentially, and the solid–solid interfacial reaction during aging and the eutectic reaction during reflow soldering were investigated in the present work. After storage at room temperature for 1 week, three phases of AuSn, AuSn2 and AuSn4 were sequentially formed at the Au/Sn (10 μm/10 μm) interface, and the thickness of this reaction region was about 5 μm. Firstly, AuSn4 was formed at the Au/Sn interface, and then AuSn and AuSn2 were formed at the Au/AuSn4 interface. After aging at 150 °C for 5 and 10 h, a similar layered structure of AuSn/AuSn2/AuSn4 was also observed. Due to the faster diffusion of Au to Sn layer, all the Sn elements were consumed after aging at 150 °C for 15 h and AuSn4 layer gradually transformed into AuSn and AuSn2 layers. For the specimen of Au/Sn (9 μm/6 μm) films on Si chip, a bamboo-shoot-like microstructure of Au5Sn/AuSn/AuSn2 was formed in the reaction region after reflowed at 280 °C for 10 s; while a typical two-phase (Au5Sn and AuSn) eutectic microstructure was formed after reflowed at 280 °C for 60 s.