| Summary: | 碩士 === 長庚大學 === 電子工程學研究所 === 97 === In this study, we investigated the thermal stability of Ni/Ag-based
alloy contacts on p-type GaN, and compared the thermal stability for
reflectance and specific contact resistance of Ni/Ag, Ni/Ag/Au, and
Ni/Ag/Ti/Au, respectively. For the Ni/Ag/Ti/Au contact, NiO was formed
by thermal annealing process and provided the characteristics of Ohmic
contact and high transmittance. Furthermore, in this contact structure, Ag,
Ti, and Au layer play the role of the reflector, diffusion barrier layer, and
anti-oxidation layer, respectively. The specific contact resistance is
5.3×10-3 -cm2, and the reflectivity may achieve 98% (@465 nm) under
the 500℃/5 min thermal annealing condition in O2 ambiance.
In this thesis, we developed the fabrication of the large-area (1mm × 1mm)
vertical structured GaN-based Light-Emitting Diodes (LEDs) with copper
electroplating and laser lift-off techniques. Moreover, by patterning the
thick photoresist, we realized the dicing-free metal substrate GaN-based
LEDs and successfully prevented the leakage current of the devices
caused by metal substrate laser cutting. We also solved the problem of the
copper substrate deformation after sapphire removing by laser lift-off
technique.
|
|---|
