Title :
Improved neutron radiation hardness for Si detectors: application of low resistivity starting material and/or manipulation of Neff by selective filling of radiation-induced traps at low temperatures
Author :
Dezillie, B. ; Li, Z. ; Eremin, V. ; Bruzzi, M. ; Pirollo, S. ; Pandey, S.U. ; Li, C.J.
Author_Institution :
Brookhaven Nat. Lab., Upton, NY, USA
fDate :
6/1/1999 12:00:00 AM
Abstract :
Radiation-induced electrical changes in both space charge region (SCR) of Si detectors and bulk material (BM) have been studied for samples of diodes and resistors made on Si materials with different initial resistivities. The space charge sign inversion fluence (Φ inv) has been found to increase linearly with the initial doping concentration (the reciprocal of the resistivity), which gives improved radiation hardness to Si detectors fabricated from low resistivity material. The resistivity of the BM, on the other hand, has been observed to increase with the neutron fluence and approach a saturation value in the order of hundreds kΩ cm at high fluences, independent of the initial resistivity and material type. However, the fluence (Φs), at which the resistivity saturation starts, increases with the initial doping concentrations and the value of Φ s is in the same order of that of Φinv for all resistivity samples. Improved radiation hardness can also be achieved by the manipulation of the space charge concentration (Neff) in SCR, by selective filling and/or freezing at cryogenic temperatures the charge state of radiation-induced traps, to values that will give a much smaller full depletion voltage. Models have been proposed to explain the experimental data
Keywords :
neutron effects; radiation hardening (electronics); silicon radiation detectors; space charge; Si; Si detectors; cryogenic temperatures; depletion voltage; improved neutron radiation hardness; initial doping concentration; initial doping concentrations; low resistivity material; low resistivity starting material; radiation hardness; radiation-induced electrical changes; radiation-induced traps; resistivity saturation; selective filling; space charge concentration; space charge region; space charge sign inversion fluence; Conductivity; Diodes; Doping; Filling; Neutrons; Radiation detectors; Resistors; Silicon radiation detectors; Space charge; Thyristors;
Journal_Title :
Nuclear Science, IEEE Transactions on