1. Parametric study of CMOS Photodetectors Computer Aided Lab CL2
Patrick Pittet, Francis Calmon, Laurent Quiquerez
3rd International Summer School on INtelligent Signal Processing for FrontIEr Research and Industry September 2015, Hamburg, Germany

2. Introduction
Conventional approach One photodiode per pixel
CMOS image sensors are now widely used (mobile phone camera, etc …). This lab is focused on the key parameters for the design of photodiodes in a given CMOS technology.
Multi-Buried junction approach

3. Introduction TCAD : process and device simulation tools
TCAD process and device simulation tools may be used to evaluate the main characteristics of the designed photo-detection structure. (It is noted that it may be challenging to get the process parameters for CMOS commercial technologies)
TCAD : process and device simulation tools
Effect of Anti Reflective coating
Impact generation rate in an Avalanche PhotoDiode

4. Introduction
Advanced electronic design automation (EDA) tools for IC design (Cadence) may be used to evaluate the main electrical characteristics of the designed photo-detection structure with its FE electronics, and to implement this structure and electronics (layout with post layout capability). CMOS technology parameters electrical are provided through a design kit.
Advanced electronic design automation (EDA) tools for IC design (Cadence)
® Nick Waltham Rutherford Appleton Laboratory

5. Introduction TCAD and EDA tools are quite complex
The Lab is implemented with a Matlab based tool to cover the different aspects of the photodetector design.
The Lab is organized in three levels
Wavelength sensitive light to silicon interactions
Parametric study of CMOS photodiode design
Special focus on CMOS multi-buried junction photodetectors

6. Goals of the lab
By the end of the lab, you should have a better understanding of typical photodiode sensitivity response curves
® AustriaMicroSystems
ILD: Interlevel Dielectric oxide
FOX: Field Oxide
You should have also some ideas for implementation of different photodiode structures in a given CMOS design process
Two photodiode structures implemented in the same CMOS process

7. Buried Quad junction photodetector (BQJ)
Goals of the lab
You should better understand the specific characteristics of multi-buried junction detectors
Buried Quad junction photodetector (BQJ)

8. Wavelength sensitive light to silicon interactions
Each level starts with a short review of the background necessary for a good understanding of the level and it is then followed by a practical training
Studied level 1 : passivation /AR layers, absorption, e/h generation rate, ...
Level Background
Practical study

9. Parametric design of CMOS photodiodes
Studied Level 2: junction depth, biasing, doping levels, temperature

10. Multi buried junction photodetectors
Studied level 3: Buried double and quadruple junctions spectral characteristics, signal processing, wavelength sensitive detection
Background

11. Conclusion
Thanks for your attention and see you for the LAB …