All-Inorganic Hermetic Packaging of Deep-Ultraviolet Light-Emitting Diodes Through Laser Localized Heating and Welding

Deep-ultraviolet light-emitting diodes (DUV-LEDs) represent a new generation of ultraviolet light sources with applications in sterilization, medical health, and biological detection. However, the traditional organic packaging is unable to meet the rigorous requirements of highly reliable high-power DUV-LEDs. In this work, an all-inorganic hermetic packaging solution based on laser localized heating and welding was developed for high-power DUV-LEDs. The parameters of laser localized welding were optimized to obtain a high-strength, crack-free welded joint. In the transition welding mode, the packaging cavity displays excellent gas tightness with a leakage rate of $1.25\times 10^{-{9}}~\text {Pa}\cdot \text {m}^{{3}}$ /s and the welded joint achieves high shear strength of 184.8 MPa. At a driving current of 350 mA, the voltage and light output power (LOP) of the packaged DUV-LED are 6.172 V and 60.44 mW, respectively. After the accelerated aging test for 250 h, the LOP of hermetic packaged DUV-LED exhibited a mere 3.24% reduction, in contrast to the 31.76% and 41.18% declines in traditional semi-inorganic packaged and unpackaged DUV-LEDs, respectively. Our work provides a meaningful guidance and solution for the highly reliable and board-level packaging of DUV-LEDs.