High efficiency membrane light emitting diode fabricated by back wafer thinning technique

We demonstrate the double-side process for back wafer thinning of epitaxial film which leads to improved performance of freestanding membrane light emitting diode (LED) on GaN-on-silicon platform. The current-voltage (I-V), capacitance-voltage (C-V), and electroluminescent measurements are conducted to characterize freestanding membrane LED. After the removal of silicon substrate and back wafer thinning of epitaxial film, the I-V characteristics of membrane LED are significantly improved, and the negative capacitance accompanied by remarkable light emission becomes stronger for thinner membrane LED. The experimental results clearly exhibit the strong membrane thickness dependence. The electroluminescent intensity of membrane LED with the membrane thickness tm ∼ 3.74μm is ∼12.4 times higher than that of LED with silicon substrate. This work opens a feasible way to form high efficiency surface emitting device on GaN-on-silicon platform.