We report our results on InGaNAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) in the 1.3 µm range. The epitaxial structures were grown on (1 0 0) GaAs substrates by metalorganic chemical vapour deposition (MOCVD) or molecular beam epitaxy (MBE). The nitrogen composition of the InGa(N)As/GaAs quantum-well (QW) active region is 0-0.02. The long-wavelength (up to 1.3 µm) room-temperature continuous-wave (RT CW) lasing operation was achieved for MBE-and MOCVD-grown VCSELs. For MOCVD-grown devices with n-and p-doped distributed Bragg reflectors (DBRs), a maximum optical output power of 0.74 mW was measured for In 0.36 Ga 0.64 N 0.006 As 0.994 /GaAs VCSELs. A very low J th of 2.55 kA cm −2 was obtained for the InGaNAs/GaAs VCSELs. The MBE-grown devices were made with an intracavity structure. Top-emitting multi-mode 1.3 µm In 0.35 Ga 0.65 N 0.02 As 0.98 /GaAs VCSELs with 1 mW output power have been achieved under RT CW operation. A J th of 1.52 kA cm −2 has been obtained for the MBE-grown In 0.35 Ga 0.65 N 0.02 As 0.98 /GaAs VCSELs, which is the lowest threshold current density reported. The emission characteristics of the InGaNAs/GaAs VCSELs were measured and analysed.
Redistribution layer (RDL) is an integral part of 3D IC integration, especially for 2.5D IC integration with a passive interposer. The RDL allows for fans out of the circuitries and allows the lateral communication between the chips attached to the interposer. There are at least two ways to fabricate the RDL, namely (a) polymers to make the passivation and Cu-plating to make the metal layer, and (b) semiconductor back-end-of-line Cu damascene. In this study, the materials and processes of these methods are presented. Emphasis is placed on the Cu damascene method.
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