3D detectors are used for detecting ionizing radiation and particles in high energy physics experiments. 3D detectors have doped electrodes penetrating through the entire substrate. The generated carriers are collected on the electrodes. Compared to the microstrip and pixel detectors, 3D detectors have the advantages of fast collection time, active edge (no dead area at the edges), low depletion voltage, and high radiation hardness. However, the processing of 3D detectors is very complex.

SINTEF MiNaLab is manufacturing 3D detectors on 250 µm thick silicon wafers. The electrode fabrication is based on our extensive activity on deep reactive ion etching.

Sketch of a Full-3D sensor. The p+ and n+ electrodes are processed inside the p-- silicon bulk. The active edges of the sensor are made from trench electrodes that surround the sides of the 3D sensor. Sensitivity extends to within a few microns of the physical edge.

Published January 8, 2008

SEM.image of a cross-section of the 3D detector. We can see holes etched for the electrodes in the substrate.