Fabrication of 3D Silicon Detectors

Abstract

Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

3D silicon sensors: Design, large area production and quality assurance for the ATLAS IBL pixel detector upgrade

“…Thus, alternative solutions are needed. SNF/SINTEF [39] and FBK [30] deposit a temporary metal layer which allows I-V tests to be performed in each tile. This aluminium layer is deposited at the end of the fabrication process.…”

Manufacturability and Stress Issues in 3D Silicon Detector Technology at IMB-CNM

“…They pointed to two origins of the high stress: Different oxide thickness between front and backsides of the wafers, leading to a bow around −130 μm [ 31 ]. Silicon nitride was deposited to avoid this asymmetry, and bow was reduced to +20 μm [ 33 ]. In both cases, wafer thickness was not directly specified, but if it was measured on the wafer mentioned in those papers (process wafer of 250 μm bonded on a 350 μm support wafer) these bow values imply really a large amount of stress, insuperable on thinner wafer, or after grinding of the support wafer; Polysilicon filling of the electrodes also induced a large stress, but this was mitigated by careful handling and planning [ 33 ].…”

3D Detectors

“…This contains the electric field and also allows the detector to be active all the way to the edge of the device. Full 3D detectors have been fabricated at both Sintef [11,12] and Stanford [7]. Sensors that are compatible with the ATLAS FE-I3 [13] front-end pixel amplifier chip have been fabricated at Sintef and successfully made into a module and tested at CERN.…”