Regions

Overview

One of the most important features of the Aquarius's device modelling capabilities is the ability to define the geometry of a device's regions using the Rectangle, Rounded Rectangle, Polygon and Import from CSV drawing functions. After the outline geometry of a device has been drawn, the regions properties can be defined and material properties assigned to them.

Usage Instructions

To define a region:

1. From the Menu, select Define -> Region and select the type of geometry you would like to define (Rectangle, Polygon etc.).

2. Use your cursor and mouse buttons to define the region shape. Or if importing geometry from a .csv file, select the file you want to use.

3. Once the region's shape has been defined the region properties dialog box will appear. Use this dialog to set the region's properties.

Parameters

General

Name	Description	Unit
Name	A unique identifier for the region.	-
Material	Used to define the material properties of the region.	-
Colour	Used to define visual colour of the region (Not used in the solver).	-

The properties of these materials can be fully customised by the user during setup of the device model. There are two general types of semiconductor can be defined, namely:

• Constant Bandgap (e.g. Si, GaAs, SiC)
• Variable Bandgap (e.g. AlGaN, AlGaAs).

Doping

Name	Description	Unit
Acceptor	Used to define the acceptor doping concentration in the region.	Atoms/cm³
Donor	Used to define the donor doping concentration in the region.	Atoms/cm³

Composition

After a region has been defined, the user can specify a constant compositional profile over the region. The mole fraction X for a ternary compound and both X and Y mole fractions for quaternary materials can be specified. This command sets a constant values in a specified region.

Name	Description	Unit
Mole Fraction X	Used define the mole fraction X. Value range between 0 and 1.	-
Mole Fraction Y	Used define the mole fraction Y. Value range between 0 and 1.	-
Force All Edges to Specified Composition	Forces all the edges of a defined region to have the compositions defined by mole-fraction parameters. Options: [True, False]	-

Point Coordinates

Once a region has been defined, users can modify its geometric points to adjust its shape. Users can add, edit, and delete points as needed.

• Editing Coordinates: Modify the region’s coordinates by directly editing the values in the table cells.
• Adding a Point: Click the Add button to insert a new point.
• Deleting a Point: Select the point to be removed and click Delete.

The region points are specified in a clockwise direction, so ensure they remain in the correct order to avoid inverting the shape.

Each point has two parameters.

Name	Description	Unit
X	Used to define the X coordinate.	Microns
Y	Used to define the Y coordinate.	Microns