tree_ring_validation

Effect: Tree rings

During the growing of silicon boules the doping percentage can vary over time building "tree-ring" like structure in doping concentration. Much like a n-p junction, the gradient in doping establishes a static lateral electric field causing electrons to drift laterally into adjacent pixels while traveling through the silicon bulk.

For introduction see Need Link

Contact person(s) if any:

Craig Lage, Mike Jarvis

Reference Material

See talk by Craig Lage here

Data Provenance:

Data for validation taken from 5 sensors on TS3 at BNL (4 ITL, 1 E2V) by HyeYun Park on ????. Sensors include:

1. ITL-017
2. ITL-098
3. ITL-206
4. ITL-283
5. ITL-350
6. E2V-260

(note disagreement with summary numbers above)

Model Details

It is noticed in the data that the tree ring amplitude increase as moving away from the center. The relationship can be parameterized to a A+B*r^4 model. The tree rings can not be represented by single sinusoid. Measured spectral power is shown below:

/Users/walter/Desktop/Screen Shot 2018-03-26 at 12.33.53 AM.png (hmm! Looks like I need to put these in a repo first!)

Based on the Fourier transform of the data, draw a range of frequencies (20 total). 75% have a spatial frequency drawn from a Gaussian with a mean of 60 pixels and a sigma of 10 pixels. 25% have a spatial frequency drawn from a Gaussian with a mean of 35 pixels and a sigma of 10 pixels. Each frequency is also given a random phase.

Validation Criteria

Area deviations and pixel shifts between the data and several simulated tree rings are compared statistically (need quantitative measure).

Validation Results

Current image (need to learn how to insert image!) show qualitative approval.

Relevant Project Team for approval if any:

Camera

Sign off date:

5/1/2019