  To cope with the High Luminosity LHC harsh conditions, the ATLAS inner
tracker has to be upgraded to meet requirements in terms of radiation hardness,
pile up and geometrical acceptance. The active edge technology allows to reduce
the insensitive area at the border of the sensor thanks to an ion etched trench
which avoids the crystal damage produced by the standard mechanical dicing
process. Thin planar n-on-p pixel sensors with active edge have been designed
and produced by LPNHE and FBK foundry. Two detector module prototypes,
consisting of pixel sensors connected to FE-I4B readout chips, have been tested
with beams at CERN and DESY. In this paper the performance of these modules are
reported. In particular the lateral extension of the detection volume, beyond
the pixel region, is investigated and the results show high hit-efficiency also
at the detector edge, even in presence of guard rings.
