Processing of ultra-thin silicon sensors for future e/sup +/e/sup -/ linear collider experiments

R&D paths of pixel detectors for vertex tracking and radiation imaging

“…The ALICE upgrade baseline design is also based on monolithic pixels for an overall material budget 0.3-0.4 % X 0 / layer with the sensor contributing ∼20%. DEPFET sensors can be thinned to 50 µm in the sensitive region, using a wafer bonding technology, retaining a frame which ensures the stiffness of the mechanical module [41]. Thin DEPFETs are under development for BELLE-II [42,43].…”

“…On the fabrication side, substrate thicknesses in the order of 150 µm are still suitable for production with standard equipment. Lower thicknesses can be obtained either by local thinning of the substrate [86] or by using a support wafer which is later removed [87]. As an alternative, in epitaxial wafers the heavily doped substrate can act as an intrinsic support wafer and can finally be almost completely removed [67].…”

Radiation-hard detectors for very high luminosity colliders

“…Thinned devices with thickness 50-100 mm have been produced at ITC-irst (Trento, Italy) [15] and at the MPI Semiconductor Detector Laboratory (Munich, Germany) [16] starting from n-type FZ Si wafers with resistivity 4-6 kO cm. The substrate thinning was performed by Tetra Methyl Ammonium Hydroxide (TMAH) etching from the backside.…”

A DEPFET pixel matrix system for the ILC vertex detector

“…For the ILC vertex detector, the DEPFET detector offers the possibility to fabricate 50 mm thin devices [6] which still offer an excellent signal to noise ratio of about S=N % 40.…”