Use the Analytic Doping Model to set the doping type and concentration within a
Semiconductor Material Model domain. The concentration is defined as a function of the local coordinate system, making this doping method suitable for profiles that are convenient to express in terms of the coordinate axes.
Choose the type of dopant distribution to apply on the selected domains from the Distribution list:
User defined (the default) to enable any expression to be used to define the dopant distribution, or
Box to create a block-shaped region of uniform doping away from which the concentration decays to a background level according to a specified profile. The
Profile of the distribution away from the uniform region is selected from a list of preset functions.
Choose an Impurity type to set the species of the dopants —
Acceptor doping (p-type) (the default) or
Donor doping (n-type). Once the impurity type is selected, enter a value or expression for the
Acceptor concentration NA0 or
Donor concentration ND0 (SI unit: 1/m
3).
For a User defined Distribution input, you can use any expression in terms of the coordinate system. This expression then defines the dopant concentration through the selected domains (if a constant value is entered this simply assigns a uniform concentration to all selected domains). For a
Box distribution, a constant value must be entered and this sets the concentration within the region of uniform doping. The default value for both distributions is a constant value of 1·10
16 cm
3.
This section is available when Box is selected under
Distribution. It is used to define the location and size of the region of uniform doping.
The Base position r0 (SI unit: m) vector sets the location of the region. When
Corner is selected it describes the coordinate of the lower left front corner of the region, and when
Center is selected it describes the coordinate of the center of the region.
The default value is at the origin of the coordinate system.
The extent of the region is defined with the Width,
Depth, and
Height inputs. Only the inputs relevant to the dimension of the component to which the feature belongs are displayed, for example, in a 2D component only the
Width and
Depth are available.
Then select an option from the Specify profile length scale list —
Junction depth (available for all profiles),
Decay length (available for a Gaussian),
Gradient (available for
Linear), or
Argument factor (available for
Error function (erf)).
By default, the Specify different length scales for each direction check box is not selected. It is possible to specify a different profile length scale in each coordinate direction when this check box is selected.
For Junction depth enter a value for the
Junction depth dj (SI unit: m, default value is 1
μm) to specify the location at which the profile concentration drops to equal the
Background doping concentration Nb (SI unit: 1/m
3). The default background concentration is
User defined with a doping concentration of 1·10
15 1/cm
3. Alternately, the doping distribution from another Analytic Doping Model or
Geometric Doping Model can be used as the background concentration.
For Decay length enter a value for the
Decay length lj of the Gaussian decay. (SI unit: m, default value is 1
μm).
For Gradient enter a value for the
Gradient Ngrad of the Linear profile (SI unit: 1/m
4, default value is
−1·10
20 1/cm
4).
For Argument factor enter a value for the
Argument factor m (SI unit: 1/m, default value is 1 (1/
μm)) to specify the factor by which the coordinate values are multiplied before being operated on by the
erf function.
As when the Junction depth option is used, by default the
Specify different length scales for each direction check box is not selected. Select it to specify a different profile length scale in each coordinate direction.