This paper presents results on the effects of sintering temperature, sintering time, and contact geometry on Al/Si and Al/poly‐Si contact resistance. At sintering temperatures >450°C the resistance of p‐type contacts is virtually constant and independent of time. The resistance of n‐type contacts, particularly to poly‐Si, increases with increasing sintering temperature for T>450°C . This is attributed to the precipitation of a p‐type (Al‐doped) layer on n‐contacts during sintering. The interface resistance of both Al/Si and Al/poly‐Si contacts is independent of the length of the contact and inversely proportional to the width of the contact.

Deposition of InP by metalorganic chemical vapor deposition, simultaneously doped with both a donor (Si) and an acceptor (Zn) species during the growth, has been carried out. The incorporation of Si is not affected by the presence of Zn, but the Zn incorporation is substantially enhanced by the presence of Si. These results are consistent with the formation of donor-acceptor pairs, which has been suggested earlier to explain Zn diffusion profiles in Si-doped InP.

We report on an extensive study of the defect structure associated with catastrophic failure of GaAs-based 980 nm pump lasers. Electron beam induced current (EBIC) analysis shows that catastrophic optical damage (COD) is characterized by the introduction of high densities of extended defects in the optical cavity of the laser, in the vicinity of the output facet. The heterostructure comprising the active region of the device is interdiffused in a spherical region surrounding the region of highest defect density. In some regions, melting of the laser cavity is observed. A “fast capture” laser degradation analysis demonstrates that the COD damage initiates at the laser facet, and propagates back along the cavity with continued device stressing. COD failure under pulsed operation results in a dramatically altered defect distribution consisting of periodic arrays of dislocation tangles along the laser cavity. Successive pulses following the initial failure event result in the formation of fresh defect “packets” which are separated from the damaged region generated due to the preceding pulse by a volume of relatively defect free material. The periodicity of these defective packets is related to the magnitude of the drive current pulse at the time of failure. Following the description of the defect distribution obtained using EBIC, we employed site-specific transmission electron microscope sectioning methods to form a detailed description of the structural modifications that the device undergoes at the onset of failure.

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International audiencePhotonic devices that exploit photonic crystal (PhC) principles in a planar environment continue to provide a fertile field of research. 2D PhC based channel waveguides can provide both strong confinement and controlled dispersion behaviour. In conjunction with, for instance, various electro-optic, thermo-optic and other effects, a range of device functionality is accessible in very compact PhC channel-guide devices that offer the potential for high-density integration. Low enough propagation losses are now being obtained with photonic crystal channel-guide structures that their use in real applications has become plausible. Photonic wires (PhWs) can also provide strong confinement and low propagation losses. Bragg-gratings imposed on photonic wires can provide dispersion and frequency selection in device structures that are intrinsically simpler than 2D PhC channel guides--and can compete with them under realistic condition