Pixel Design Playground
The comprehensive pixel design tool. Configure every parameter of a BSI CMOS pixel — from silicon thickness to BARL sublayers — and see the combined effect on QE, reflectance, energy budget, and stack geometry.
Pixel Design Playground
Configure all pixel parameters and explore multi-panel results: QE spectra, layer stack visualization, and energy budget analysis powered by TMM.
Model scope
Use this browser tool for intuition, relative trends, and design-space exploration. Its local simplified model is not a substitute for RCWA/FDTD sign-off, silicon calibration, or vendor process data.
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Coupled Pixel Stack Model
This is a what-if sandbox for pixel design. Drag a slider — pixel pitch, filter thickness, silicon depth — and watch several metrics move at once because everything in a pixel is coupled. It is a quick first-pass tool to build intuition before you spend hours on a full RCWA or FDTD simulation.
The playground combines pixel pitch, color-filter thickness, BARL layers, silicon thickness, and incidence angle into one simplified stack-level optical response.
Assumptions
- The playground combines simplified optical, geometry, and sensor-metric models into one exploratory view.
- Interactions between microlens, CFA, BARL, DTI, silicon, and noise are approximate and should be validated in dedicated tools.
- The goal is relative trend ranking, not final quantitative device prediction.
Outputs
- Multi-panel summaries for optical efficiency, crosstalk tendency, full well, SNR, dynamic range, and scaling tradeoffs.
- A first-pass parameter screening table before running slower RCWA/FDTD or calibrated compact-model studies.
Validation Example
- Increasing pitch should generally raise photon collection and full well while easing diffraction pressure.
- Turning off DTI or reducing isolation should increase crosstalk indicators rather than improve every metric simultaneously.
Core Equations
- \(QE_c\): Quantum efficiency for color $c$
- \(T_{\text{CF},c}\): Color filter transmittance
- \(A_{\text{Si}}\): Absorbance in the silicon photodiode
The color channel response is approximated by filter transmission times silicon absorption.
- \(A_{\text{px}}\): Geometric pixel area
- \(p\): Pixel pitch
Area changes photon count and full-well trends even if spectral QE is unchanged.
- \(R, T\): Reflectance and transmittance
- \(A_{\text{layer}}\): Per-layer absorbance
The same conservation check is used to interpret stack losses.
Model Interpretation
- Changing one slider can shift multiple metrics because optical stacks are coupled.
- Use this for design-space triage before running RCWA or FDTD on a detailed geometry.
- The model omits lateral field maps, carrier transport, and process variation.
Coupled Knobs
- Reducing pitch lowers photon count through $A_{\text{px}}=p^2$ even when optical QE stays constant.
- Changing color-filter thickness shifts both spectral separation and parasitic absorption.
- Silicon thickness improves long-wavelength absorption but can increase crosstalk or carrier-collection burden in a real pixel.
Use As A Triage Tool
- Use large metric changes to identify promising regions, then move those candidates into TMM, ray tracing, RCWA, or FDTD.
- Compare relative trends rather than absolute numbers because the simplified browser model uses compact material spectra.
- Treat any optimum at a slider boundary as a sign that the explored design range is too narrow.
Known Missing Physics
- The playground does not solve lateral diffraction, microlens focusing, DTI confinement, or charge diffusion.
- Process variation, thickness tolerance, and material dispersion uncertainty are not sampled statistically.
- Use it to choose simulations, not to sign off a pixel stack.