To cope with the higher occupancy and radiation damage at the HL-LHC also the LHC experiments will be upgraded. The ATLAS Planar Pixel Sensor R&D Project (PPS) is an international collaboration of 17 institutions and more than 80 scientists, explorin
g the feasibility of employing planar pixel sensors for this scenario. Depending on the radius, different pixel concepts are investigated using laboratory and beam test measurements. At small radii the extreme radiation environment and strong space constraints are addressed with very thin pixel sensors active thickness in the range of (75-150) mum, and the development of slim as well as active edges. At larger radii the main challenge is the cost reduction to allow for instrumenting the large area of (7-10) m^2. To reach this goal the pixel productions are being transferred to 6 inch production lines and more cost-efficient and industrialised interconnection techniques are investigated. Additionally, the n-in-p technology is employed, which requires less production steps since it relies on a single-sided process. Recent accomplishments obtained within the PPS are presented. The performance in terms of charge collection and efficiency, obtained with radioactive sources in the laboratory and at beam tests, is presented for devices built from sensors of different vendors connected to either the present ATLAS chip FE-I3 or the new Insertable B-Layer chip FE-I4. The devices, with a thickness varying between 75 mum and 300 mum, were irradiated to several fluences up to 2e16 neq/cm. Finally, the different approaches followed inside the collaboration to achieve slim or active edges are presented.
A new module concept for future ATLAS pixel detector upgrades is presented, where thin n-in-p silicon sensors are connected to the front-end chip exploiting the novel Solid Liquid Interdiffusion technique (SLID) and the signals are read out via Inter
Chip Vias (ICV) etched through the front-end. This should serve as a proof of principle for future four-side buttable pixel assemblies for the ATLAS upgrades, without the cantilever presently needed in the chip for the wire bonding. The SLID interconnection, developed by the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. It is characterized by a very thin eutectic Cu-Sn alloy and allows for stacking of different layers of chips on top of the first one, without destroying the pre-existing bonds. This paves the way for vertical integration technologies. Results of the characterization of the first pixel modules interconnected through SLID as well as of one sample irradiated to $2cdot10^{15}$, eqcm{} are discussed. Additionally, the etching of ICV into the front-end wafers was started. ICVs will be used to route the signals vertically through the front-end chip, to newly created pads on the backside. In the EMFT approach the chip wafer is thinned to (50--60),$mu$m.
The existing ATLAS Tracker will be at its functional limit for particle fluences of 10^15 neq/cm^2 (LHC). Thus for the upgrades at smaller radii like in the case of the planned Insertable B-Layer (IBL) and for increased LHC luminosities (super LHC) t
he development of new structures and materials which can cope with the resulting particle fluences is needed. N-in-p silicon devices are a promising candidate for tracking detectors to achieve these goals, since they are radiation hard, cost efficient and are not type inverted after irradiation. A n-in-p pixel production based on a MPP/HLL design and performed by CiS (Erfurt, Germany) on 300 mu m thick Float-Zone material is characterised and the electrical properties of sensors and single chip modules (SCM) are presented, including noise, charge collection efficiencies, and measurements with MIPs as well as an 241Am source. The SCMs are built with sensors connected to the current the ATLAS read-out chip FE-I3. The characterisation has been performed with the ATLAS pixel read-out systems, before and after irradiation with 24 GeV/c protons. In addition preliminary testbeam results for the tracking efficiency and charge collection, obtained with a SCM, are discussed.
