Deep-ultraviolet LEDs with all-inorganic and hermetic packaging by 3D ceramic substrate

In this letter, an all-inorganic and hermetic packaging technology was proposed for deep-ultraviolet light-emitting diodes (DUV-LEDs). The package was fabricated by bonding the quartz cap on the three-dimensional (3D) ceramic substrate at low temperature. The bonding layer was formed by an inorganic adhesive and presented a reliable and dense state. The average air leakage rate of the packaging structure was $3.79\times 10^{-8}$ Pa $\cdot$ m3/s and the average tensile strength between quartz cap and ceramic substrate was 4.3 MPa. The peak emission intensity was at 280 nm and the peak width at half height was about 10 nm. At the current of 40 mA, the voltage was 5.63 V and the light output power was 3.0 mW. After the accelerated aging test, the light output power of packaged DUV-LEDs only decreased by 14.9%, while that of unpackaged reference decreased by 55.8%.