Setup parallels setup of the three-dimensional layer sequence database (see 12.8), which in turn follows setup of the extraction system (see 16.8). These sections should be consulted for detailed setup information, here we provide some supplemental information.
To the interface, there are two different materials:
In addition, layers that are to be used in the interface as conductors or insulators must have all of the following:
Conductor layers can have the following optional keywords defined. These control the filamentation of conductor layers carrying current in the plane of the substrate, in the direction normal to the substrate. This accounts for penetration or skin depth in planar areas of material, in the Z direction. Typically, for superconductors at least, lateral dimensions are much larger than film thicknesses, so the volume element refinement tends to keep the film thinkness unbroken in the Z direction. For accurate account of the penetration depth, this should be further subdivided, and filamentation is one way to accomplish this.
The conductor layers can be given a resistivity or conductivity with the Rho and Sigma keywords, respectively. Additionally, the Lambda parameter, which specifies the London penetration depth for superconductors, can be specified. This is for the convenience of Xic users in the superconducting electronics R&D community. In this case, Rho/Sigma specify the unpaired conductivity from the two-fluid model.
The Dielectric technology file keyword was added to support capacitance extraction. This is intended to model an explicit capacitor dielectric, and differs from Via layers in the following ways.
The present interface can take layers in any order. This is in contrast with the original interface, that required layers to alternate conductor/insulator starting with a conductor, and ordering was obtained entirely from Via references and not the layer table order.
After all possible layers from the layer table are sequenced, layers that are not used in the extracted geometry are discarded. Note that dark-field layers are inverted, as we are interested in representing the physical material. Thus, for example no structure in a Via layer (i.e., no vias) in the layout implies the presence of a continuous film of insulating material, so the layer is actually present.
The same layer sequencer is used in the Cross Section command in the View Menu. The cross section display and the interface will always agree on the ordering and planarization of the layers. This was not true with the original interface.
In addition to the layers that describe material geometry, the interface can make use of a masking layer. This allows only certain specified parts of the current cell to be evaluated. When present, geometry is clipped to objects on this layer before being processed in the interface.
By default, a layer named FHRY with purpose drawing is assumed for the masking layer. Such a layer should be defined in the technology file. It should be given a GDSII mapping to allow saving of work containing the layer to GDSII or OASIS files. As an alternative, the FhLayerName variable can be set to the name of another layer, which will instead provide the masking function.
Finally, the layers used in terminal definitions should be configured into the technology file. Generally, there is an Xic layer corresponding to each conducting layer, with a purpose name ``fhterm'' and the same base layer name. In order to save the layout with terminals as GDSII or OASIS, a GDSII layer mapping should be applied for these layers.