MBE fabrication of GaN-based light emitting diode on MOCVD grown GaN-on-Si template and application for optical MEMS

GaN-based light emitting diode (LED) structure (n-GaN/quantum wells/p-GaN) was grown by molecular beam epitaxy (MBE) on a GaN-on-Si template substrate grown by metal organic chemical vapor deposition (MOCVD). The GaN crystal grew continuously on the template and surface of the GaN film was flat. We fabricated very thin comb-shaped electrodes on the GaN film as semi-transparent metal contacts. Blue light emission was observed from the semi-transparent electrode region on p-GaN crystal at peak wavelength of 410nm at room temperature. On the other hand, we propose a light distribution variable device which changes the light direction emitted from LEDs by integration of GaN-based LEDs and Si micromachining technology. To demonstrate the light distribution variable device, we fabricated micro stage from the template substrate as preliminary experiment for the light distribution variable device. The device was successfully fabricated and we observed that the stage moved about 40 μm at the voltage of 100 V. These values are almost same as calculated values. Photoluminescence (PL) was also observed in this device. The electric wiring has not been completed, these results demonstrate the usefulness of monolithic fabrication of GaN-Si hybrid MEMS.