High power near-UV LEDs, with wavelengths from 365nm to 410nm, were realized with an external
quantum efficiency from 12% to 45% for 365nm and 410nm, resp.
We show that the vertical LED design, coupled with the Silicon sub-mount package, gives very good
reliability that is suitable for many high power epoxy and polymer curing applications. UV LEDs are
proven to be a good replacement for high power mercury lamps currently used in the market.
High ESD endurance capability is an important issue for the extensive application of power light emitting
diodes (LEDs). Conventional ceramic varistor based on sintered bulk zinc oxide (ZnO) with various metal oxides as
additives have widely used in surge protection device by grounding the excessive current for a long time. Those sintered
bulk ZnO devices are known to exhibit high nonlinearity coefficient (α>50) and good reliability for many commercial
applications. However, sintering manufacture method limits the practicability of integrating bulk ZnO varistor with other
semiconductor devices. In this research, we report on the thin-film ZnO produced by sputtering system and post-heat
treatment which have shown good varistor characteristics. The nonlinear coefficients (α) in the correspondent current
-voltage (I-V) curve can up to 50 at a high electric field of 1.1 kV/cm, and, with efficiently resolving thermal generated
by high injected current, this thin film varistor can conduct current to the density as high as 20A/cm<sup>2</sup> successfully. In
addition, our thin film varistor devices combined with power LEDs by gold wires bonding revealed an improved
electrostatic discharge (ESD) ability of up to 400V apparently. This wire bonding configuration will be modified to a
flip-chip LED with the ZnO/Si submount in the future. Sputtering and annealing are two commonly used processes in
general semiconductor manufacture procedures which are adopted in our ZnO thin film deposition. Therefore, our
proposed method have provided a new possible solution to integrate not only LEDs but also other semiconductor devices
with thin film varistor owning surge protection capability, especially to accomplish an on-chip surge protection.