Comparison between TCAD simulated and measured carrier lifetimes in CMOS photodiodes using the Open Circuit Voltage Decay method

The control and prediction of minority carrier lifetime are crucial for the design of photodiodes, especially for CMOS image sensors, because signal electrons must be captured before recombination. Analytic models have been developed but do not allow accurate and reliable lifetime estimations according to complex photodiode architecture. In this work, we show for the first time that mixed-mode TCAD simulations produce accurate and reliable results for realistic photodiode designs. To arrive at this conclusion, we have performed measurements and simulations on two different photodiodes using the Open Circuit Voltage Decay method.

► We measured two photodiodes using the Open Circuit Voltage Decay method.
► We analyzed and extracted carrier lifetime from the measurement.
► We simulated this measurement using TCAD tools.
► We compared simulated and measured lifetime and showed a very good matching.
► It demonstrates the capability of TCAD to simulate lifetime in complex structure.