Comparison of simulated and measured results for a square sided inductor

questex03.in : Comparison of simulated and measured results for a square sided inductor

Requires: QUEST Minimum Versions: QUEST 2.0.2.R

To load and run this example, select the Load example button in DeckBuild. This will copy the input file, GDSII file and results to your current working directory. Select the run button to execute the example.

This example is based on an IBM paper by Rob Groves et al. "Temperature Dependence of Q in Spiral Inductors Fabricated in a Silicon Germanium BiCMOS Technology" IEEE BCTM 9.3 pp. 153-156 1996. It shows the modeling of a 10nH spiral inductor that can be compared to measured results from the reference.

The GDSII file can be viewed in Maskviews, Expert or any other Layout editing tool that can read GDSII format. The input file was created using information from the paper.

The example demonstrates how to write the technology part of the input file. The attachment of electrode names in the GDSII layout file to bond/probe pads in the circuit is achieved by declaring the layer containing the text for the electrode names twice, once with text declared and once without text declared. These two layers (one with text declared and one without) are then electrically connected with the CONNECTION command to give the structure its electrode names.

Of note in the process part is the depth of the substrate and the height of the air above the device which is included into the modelled structure volume. It is vital for accurate inductance calculations, that the full volume of inductive flux lines are included. As a general rule, a safe substrate depth and air height would be the diameter of the inductor being simulated. Since the inductor in this example has a diameter of approximately 400um, the depth of the substrate in the simulation was chosen to be 400um.

It is also important to define both the conductivity and permittivity of the substrate for accurate modeling of the quality factor, Q, versus frequency.

A two port simulation is defined by using the reserved electrode name called "subs_ground". This grounds out the reference electrode for both the "IN" port and the "OUT" port of the two port network.

All the results will be placed in a directory structure under the name "questex03_db" which was defined with SAVE command.

Three dimensional structure files can be viewed with TonyPlot3d. All other RLCG and Q versus frequency data can be viewed with TonyPlot.