Abstract: A diffusion preventing barrier spike is disclosed. The spike prevents diffusion of dopants into another layer without forming a pn junction in the layer. The spikes are illustratively Al or an aluminum containing material such as AlAs and have a thickness on the order of 1 nm. The spikes of the present invention may be used to stop dopant diffusion out of a doped layer in a variety of III-V semiconductor structures, such a InP-based PIN devices.

Abstract: A method and apparatus are disclosed for cleaving a crystalline wafer, such as indium phosphide (InP) or gallium arsenide (GaAs) wafers. A wafer can be scribed with a scribing tool using a straight edge that does not contact the wafer. The wafer is held firmly in place using a vacuum chuck. The wafer can rest in a pocket depressed into the surface of a wafer holder at a depth greater than the wafer thickness. The sliding straight edge can be placed with a perpendicular or parallel orientation to the flat alignment region of the wafer. The straight edge sits on legs that hold the sliding straight edge above the wafer and glide through slots or grooves in the wafer holder. The sliding straight edge can be stopped at the desired alignment point using a scale embedded into the wafer holder. The vacuum holding the wafer in place is under a constant leak by way of a groove from the vacuum chuck to outside air. Thus, the wafer does not stick to the vacuum chuck and can be easily removed without breakage.

Abstract: The invention is an optical device and method of fabrication which mitigates the problem of Zn migration in the cladding and waveguide regions. The contact region includes carbon, which acts as a p-type dopant in ternary semiconductor material. The contact layer is made of InGaAs or InGaAsP, and the invention is most advantageously used in an electroabsorption modulated laser or capped mesa buried heterostructure laser.