[en] Many efforts were dedicated in the last decade at CERN and BNL to create the quark gluon plasma by means of ultra-relativistic heavy ion collisions. The failure in getting so far a clear signature assignable to this new phase of nuclear matter was interpreted as being due to the lack in sufficient heavy ion energy needed to create the hot and dense QGP. The STAR and ALICE projects to be implemented at RHIC (Brookhaven) and LHC (CERN), respectively are devoted to the realization of these conditions. After year 2005 the LHC will produce lead beams of the energy √ s = 6,300 GeV/A while RHIC will supply starting from 1999 gold beams of √ s = 200 GeV/A. The paper gives a general description of ALICE, particularly, of the two final detection stages of the Inner Tracking System, in the design and realization of which the SUBATECH is directly engaged. A special effort was directed for the realization of silicon microstrip detectors (SMD), on one hand, and towards the computerized simulations describing the SMD in terms of spatial resolution and charge correlations, on the other hand. Also, the physicists from SUBATECH are participating in the STAR experiment, particularly in the development of its silicon vertex tracker (SVT) by means of an additional detection module based on SMDs. Its insertion between the external stage of SVT and the time projection chamber will enhance significantly the performances of STAR. The optimization of tracking software as well as the development of new algorithms, taking into account the possibilities of the inserted module, are now underway