Speaker
Description
Doping concentration is a fundamental property in semiconductor manufacturing influencing the electrical properties and reliability of silicon sensors. Three-dimensional mapping of dopant distribution provides a deeper understanding of sensor characteristics, including depletion voltage, breakdown behavior, and charge collection properties. Uniform doping across large sensor areas and depths is critical for achieving high manufacturing yield and device reliability. However, conventional measurement techniques are limited when applied to modern low-doping, high-resistivity silicon sensors commonly used in high-energy physics and photon science. Secondary ion mass spectrometry provides high-resolution measurements but are insensitive to doping concentrations below 1×10^12 cm^(-3), while capacitance-voltage profiling and spreading resistance profiling offer only coarse granularity.
We present a novel 3D doping imaging technique based on the backside-pulsing [1], which enables pixel-wise capacitance–voltage (C–V) measurements together with charge-integrating readout ASICs. Measurements were performed on a 1×1 cm^2 silicon sensor bump-bonded to the MÖNCH ASIC [2] with 25 μm pixels, and on a 4×8 cm^2 silicon sensor bump-bonded to JUNGFRAU ASICs [3] with 75 μm pixels. This method yields 3D doping concentration maps around 3×10^11 cm^(-3) with a micrometer-scale resolution (down to 25 µm laterally and 10 µm in depth) and a relative uncertainty typically below 3%, revealing doping ring structures and anomalous regions. The approach holds promise for a broad range of detector characterization and sensor development applications.