We have many options available for custom runs. It is possible to combine many of these with standard MPW options such as direct metallization, tri-layer metallization, and deep trenches. Currently available dedicated fabrication options are listed here: - Custom cladding oxide thickness We can deposit cladding oxide thicknesses up to 3 μm. Typical oxide thicknesses are 1 μm and 2.2 μm. - Different silicon device layer thickness We have SOI wafers with the following device layer thicknesses: 145 nm, 220 nm, 300 nm, and 500 nm. As the device layer thickness increases, the minimum feature size and spacing increase to maintain a suitable aspect ratio. - Multi-layer alignment with 50 nm accuracy Multi-layer alignment can be used to accurately place metal features or create partially-etched silicon structures such as rib waveguides. - Positive-tone structures Positive tone structures include photonic crystal cavities. - Multiple silicon etch depths We can etch partially into the silicon to create structures such as rib waveguides and gratings. The etch depth can be customized, and the error in the etch depth is ± 10 nm. - Oxide via etching Windows in the cladding oxide allow for electrical connections to metal layers fabricated using the standard direct metallization option. The metal layers are deposited directly on the silicon or buried oxide layers. The window in the oxide, called the oxide via, must terminate on a metal layer. - Selective buried oxide etching The buried oxide layer can be used as a sacrificial material for micro- or nanomechanical devices. By selectively removing the buried oxide, we can release mechanical devices for optomechanics and other applications. - Custom metal levels and choices of metals We have many custom metals available including Cr, Au, Al, TiW, W, and Ni. When combined with the custom oxide cladding option, these metals can be placed at any oxide depth for electrical circuits or custom heaters. - Through-cladding windows We etch through the oxide cladding to create windows that open onto the silicon or buried oxide layers. - Deep trench with full silicon handle etch A variation on the standard deep trench process. We perform a deep silicon etch during the deep trench process to etch fully through the silicon handle layer. The end result is a smooth chip edge from the top of the cladding to the bottom of the handle. This is useful when fiber arrays with large dimensions are required for edge coupling. - Fiber bonding service Attachment of 2, 4 and 8-fiber arrays onto dies for light input/output. - Measurement services In-house semi-automatic measurement of vertically coupled devices in C-band. - Active Devices and Custom Doping Custom doping levels and species in silicon for active photonic devices (detectors, modulators, heaters, etc.).
