Quaternary alloys material model properties

Quaternary Alloys

Quaternary alloys can be created by using a ternary alloy and a compound semiconductor as base materials. The ternary alloy (which itself is created by mixing two compound semiconductors) is an 'alloy' type material and it should be converted to 'semiconductor' type before it can be used as a base material for the quaternary alloy. The compound semiconductor will in most cases be available in the material database. As an example, steps to creating AlxGayIn1-x-ySb in CHARGE is shown below:

Creating Al_xGa_yIn_1-x-ySb

The Al_xGa_yIn_1-x-ySb quarternary alloy can be created by mixing AlSb, GaSb, and InSb. The first step would be to mix InSb and AlSb together to create In_1-xAl_xSb.  Next, the alloy is converted into a semiconductor type material, and then finally, the semiconductor model of In_1-xAl_xSb is mixed with GaSb to get Al_xGa_yIn_1-x-ySb.

Step 1: Create alloy model for In_1-xAl_xSb

Create a new alloy using the 'Ternary Alloy' option under the 'new material' button. Choose InSb as the first base material and AlSb as the second base material. Choose the interpolation option to be 'multi valley'.

Set the name to be In(1-x)Al(x)Sb. Since InSb is the first and AlSb is the second base material, the alloy mole fraction will be (InSb)_1-x(AlSb)_x or In_1-xAl_xSb.

Step 2: Convert In_1-xAl_xSb to semiconductor type material

Use the "Convert to semiconductor" option available in the duplicate menu to convert the created alloy into a semiconductor type of material:

This enables InAlSb to be used as a base material in the next step. The option will prompt the user to set the mole fraction x, here corresponding to AlSb. 

It should be noted that the values obtained for the new semiconductor are approximations, and the created material may still require user inspection. The minimum semiconductor material properties that are necessary to create the 'semiconductor' material model of In_1-xAl_xSb are permittivity (epsr), work function (W), bandgap (Eg), electron and hole effective mass (mn, mp), electron and hole mobility (mun, mup), and the carrier lifetimes for SRH recombination (taun, taup).

Step 3: Create the quaternary alloy Al_xGa_yIn_1-x-ySb

Finally, use the new semiconductor material model for In1-xAlxSb (In(0.55)Al(0.45)Sb) and GaSb to create a 'Ternary Alloy' material model for AlxGayIn1-x-ySb.  Name the material Al(0.45)Ga(y)In(1-0.45-y)Sb.