Crack-free InGaN multiple quantum wells light-emitting diodes structures transferred from Si (111) substrate onto electroplating copper submount with embedded electrodes

Abstract

Crack-free InGaN multiple quantum wells (MQWs) light-emitting diodes with embedded electrode structures (EE-LEDs) were transferred from Si (111) substrate onto the electroplating copper submount. Crystalline quality was investigated by the high resolution x-ray diffraction (HR-XRD) measurement, in which no obvious deteriorations were found in the MQWs structure after the LEDs transferred from silicon substrate onto copper except for a partial residual strain relaxation in the film. The strain relaxation after silicon removal leads to a reduction in quantum confined stark effect (QCSE), which results in the enhancement of internal quantum efficiency (IQE). In comparison to the conventional LEDs on silicon substrate, the light output of the EE-LEDs on copper was enhanced by 122% at an injection current of 350 mA. Besides the enhancement of IQE, the improvement is also attributed to the following factors: the removal of the absorptive substrate, the inserting of the metal reflector between the EE-LEDs structure and the copper submount, the elimination of the electrode-shading, and the rough surface of the exposed AlN buffer layer.