High energy proton damage effects in thin high resistivity FZ silicon detectors

摘要

The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) will demand the inner most layers of the vertex detector to sustain fluences of about 10~(16) charged hadrons/cm~2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field thin silicon detector assemblies are proposed as a possible solution for this challenge. The radiation tolerance of 50 μm thin high resistivity float zone (FZ) devices has been studied for 24GeV/c protons in the fluence range between 4x10~(13)cm~(-2) and 8.6 x 10~(15)cm~(-2). For the manufacturing of such thin devices, a technology based on direct wafer bonding and deep anisotropic etching was used. Annealing measurements at 80℃ have shown that the introduction rate g_C in the stable damage component is about the same as observed for oxygen enriched FZ detectors and that the fluence dependence of the reverse annealing amplitude N_Y exhibits a saturating function. It is also demonstrated that the annealing behavior of the reverse current related damage parameter a is independent on the fluence and the silicon material parameters. Charge collection efficiency (CCE) measurements were performed using 5.8 MeV α-particles. After fully annealing for about 31 days at 80℃ CCE was determined by extrapolation to be 66% at 10~(16)p/cm~2.