DopingProfileReader

Description

Adds a doping profile to the detector from one of the supported sources. By default, detectors do not have a doping profile applied. A doping profile is required for simulating the lifetime of charge carriers. It is not used for the calculation of the electric field inside the sensor. The profile is extrapolated along z such that if a position outside the sensor is queried, the last value available at the sensor surface is returned. This precludes edge effects from charge carriers moving at the sensor surfaces.

The following models for the doping profile can be used:

• For constant, a constant doping profile is set in the sensor
• For regions, the sensor is segmented into slices along the local z-direction. In each slice, a constant doping concentration is used. The user provides the depth of each slice and the corresponding concentration.
• For mesh, a file containing a doping profile map in APF or INIT format is parsed.

Parameters

• model : Type of the doping profile, either constant, regions or mesh.
• file_name : Location of file containing the doping profile in one of the supported field file formats. Only used if the model parameter has the value mesh.
• field_mapping: Description of the mapping of the field onto the sensor or pixel cell. Possible values are SENSOR for sensor-wide mapping, PIXEL_FULL, indicating that the map spans the full 2D plane and the field is centered around the pixel center, PIXEL_HALF_TOP or PIXEL_HALF_BOTTOM indicating that the field only contains only one half-axis along y, HALF_LEFT or HALF_RIGHT indicating that the field only contains only one half-axis along x, or PIXEL_QUADRANT_I, PIXEL_QUADRANT_II, PIXEL_QUADRANT_III, PIXEL_QUADRANT_IV stating that the field only covers the respective quadrant of the 2D pixel plane. In addition, the PIXEL_FULL_INVERSE mode allows loading full-plane field maps which are not centered around a pixel cell but the corner between pixels. Only used if the model parameter has the value mesh.
• field_scale: Scaling factor of the electric field in x- and y-direction. By default, the scaling factors are set to {1, 1} and the field is used with its physical extent stated in the field data file.
• field_offset: Offset of the field in x- and y-direction. With this parameter and the mapping mode SENSOR, the field can be shifted e.g. by half a pixel pitch to accommodate for fields which have been simulated starting from the pixel center. The shift is applied in positive direction of the respective coordinate. Only used if the model parameter has the value mesh.
• doping_concentration : Value for the doping concentration. If the model parameter has the value constant a single number should be provided. If the model parameter has the value regions a matrix is expected, which provides the sensor depth and doping concentration in each row.
• doping_depth : Thickness of the doping profile region. The doping profile is extrapolated in the region below the doping_depth. Only used if the model parameter has the value mesh.

Plotting parameters

• output_plots : Determines if output plots should be generated. Disabled by default.
• output_plots_steps : Number of bins in both x- and y-direction in the 2D histogram used to plot the doping concentration in the detectors. Only used if output_plots is enabled.
• output_plots_project : Axis to project the doping concentration on to create the 2D histogram. Either x, y or z. Only used if output_plots is enabled. Default is x (i.e. producing a slice of the yz plane).
• output_plots_projection_percentage : Percentage on the projection axis to plot the doping concentration profile. For example if output_plots_project is x and this parameter is set to 0.5, the profile is plotted in the yz plane at the x-coordinate in the middle of the sensor. Default is 0.5.
• output_plots_single_pixel: Determines if the whole sensor has to be plotted or only a single pixel. Defaults to true (plotting a single pixel).

Usage

In the following example a doping profile map in APF format is loaded:

[DopingProfileReader]
model = "mesh"
file_name = "example_doping_profile.apf"
field_mapping = PIXEL_FULL

In the next example two regions with constant doping are used. Down to a depth of 25um the doping concentration is $6\times 10^{11} \,\text{cm}^{-3}$, while below it the doping is set to $5\times 10^{18} \,\text{cm}^{-3}$:

[DopingProfileReader]
model = "regions"
doping_concentration = [[25um,6e11/cm/cm/cm],[50um,5e18/cm/cm/cm]]

Finally, a constant doping of $-2.13\times 10^{15} \,\text{cm}^{-3}$ is set for the entire sensor:

[DopingProfileReader]
model = "constant"
doping_concentration = -2.13e+15/cm/cm/cm