Detector thickness effects on nanosecond-gated imager response.

Area of Science:

• * Physics
• * Materials Science

Background:

• * Hybrid CMOS multi-frame imagers with nanosecond exposure times are vital tools in high energy density physics and inertial confinement fusion research.
• * Detector thickness is a critical factor influencing both the quantum efficiency and temporal response of these imaging systems.

Purpose of the Study:

• * To investigate the impact of silicon detector thickness on the performance of hybrid CMOS imagers.
• * To analyze the temporal response of imagers with varying detector thicknesses, down to 2 nanosecond exposure times.
• * To correlate detector thickness with charge carrier collection, field collapse, and spatial response.

Main Methods:

• * Fabrication of Icarus hybrid CMOS imagers with silicon detector thicknesses of 8, 25, and 100 µm.
• * Examination of the temporal response of these imaging sensors with exposure times as short as 2 ns.
• * Comparison of sensor temporal response to directly measured photodiode current.

Main Results:

• * The 100-µm thick silicon detector variant exhibited extended features linked to charge carrier collection.
• * Thicker detector variants were found to be more susceptible to field collapse.
• * Charge collection time was demonstrated to affect the spatial response of the imagers.

Conclusions:

• * Detector thickness is a critical design parameter for hybrid CMOS imagers, influencing temporal and spatial performance.
• * The 100-µm detector thickness presents challenges related to charge collection and field stability.
• * Understanding these thickness-dependent effects is essential for optimizing imager performance in demanding physics applications.