The microscopic damage produced in diodes made of n-type Magnetic Czochralski (MCz) silicon by 24 GeV and 26MeV protons, up to the fluence of 1.3x1015 cm-2 1MeV equivalent neutrons, has been investigated and results are compared to the damage produced in devices made of standard Floating Zone (STFZ) silicon. It is found by means of Thermally Stimulated Currents (TSC) that the production of a radiation induced charged defect is enhanced in MCz, and might be in part responsible for the differences observed in the two materials at room temperature. The influence of defects on the sign of the space charge density has been studied by current transients at constant temperature i(T,t) and by Transient Current Technique (TCT). Type inversion is not revealed up to the highest investigated fluence. Full depletion voltage Vdep measurements versus fluence exhibits a minimum close to 2x1014 cm-2 1MeV equivalent neutrons; at the same fluence, Vdep measured as a function of annealing time changes its initial slope from positive to negative. It is shown by numerical simulations that these features can be accounted by the formation of a double junction, even in absence of type inversion.
Localized energy levels generated in Magnetic Czochralski silicon by proton irradiation and their influence on the sign of space charge density
Piemonte, Claudio;Zorzi, Nicola;
2007-01-01
Abstract
The microscopic damage produced in diodes made of n-type Magnetic Czochralski (MCz) silicon by 24 GeV and 26MeV protons, up to the fluence of 1.3x1015 cm-2 1MeV equivalent neutrons, has been investigated and results are compared to the damage produced in devices made of standard Floating Zone (STFZ) silicon. It is found by means of Thermally Stimulated Currents (TSC) that the production of a radiation induced charged defect is enhanced in MCz, and might be in part responsible for the differences observed in the two materials at room temperature. The influence of defects on the sign of the space charge density has been studied by current transients at constant temperature i(T,t) and by Transient Current Technique (TCT). Type inversion is not revealed up to the highest investigated fluence. Full depletion voltage Vdep measurements versus fluence exhibits a minimum close to 2x1014 cm-2 1MeV equivalent neutrons; at the same fluence, Vdep measured as a function of annealing time changes its initial slope from positive to negative. It is shown by numerical simulations that these features can be accounted by the formation of a double junction, even in absence of type inversion.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
