How to set the alloy fraction when using an alloy in a CHARGE simulation


Dear Teacher,
I want to use Si0.85Ge0.15 alloy in my device structure. But in database there is no option available to define fraction of different semiconductor. Can u help me to find it out?

How to see the material properties of an alloy in the material database

Hi @sourabh.jain, the alloy fraction of an alloy can be defined while using it in a geometry. As shown in the screenshot below the “material” tab has the options to define the alloy fraction which only becomes available if an alloy is chosen as the material.

Instead of defining a fixed value for the alloy fraction you can also define a linear variation in the alloy fraction inside the geometry. For more information on this take a look at this KB page: Structures - Rectangle (look under the “materials tab”).


Thankyou for replying


Hi, aalam.
Is there some option to define the fraction of alloy materials in when using a layer builder?
Thank you,


Hi Anna,

Unfortunately it looks like there is no way to set the alloy fraction from the layer builder interface. This means that you probably won’t be able to use the layer builder if you want to use alloy materials. You can however use the “GDS Import” button to import the structure and then manually assign alloys to the polygons and set the alloy fractions. You can use a script in the structure group to do this easily.


Thank you for quick reply.