DLTS andin situ C–Vanalysis of trap parameters in swift 50 MeV Li³⁺ion-irradiated Ni/SiO₂/Si MOS capacitors

Abstract

Ni/SiO 2 /Si MOS structures were fabricated on n-type Si wafers and were irradiated with 50 MeV Li 3+ ions with fluences ranging from 1 × 10 10 to 1 × 10 12 ions/cm 2 . High frequency C-V characteristics are studied in situ to estimate the build-up of fixed and oxide charges. The nature of the charge build-up with ion fluence is analyzed. Defect levels in bulk Si and its properties such as activation energy, capture cross-section, trap concentration and carrier lifetimes are studied using deep-level transient spectroscopy. Electron traps with energies ranging from 0.069 to 0.523 eV are observed in Li ion-irradiated devices. The dependence of series resistance, substrate doping and accumulation capacitance on Li ion fluence are clearly explained. The study of dielectric properties (tan δ and quality factor) confirms the degradation of the oxide layer to a greater extent due to ion irradiation.

Room temperature spectroscopy of deep levels in junction structures using barrier capacitance charging current transients

“…Deep level transient spectroscopy is traditionally used to characterize deep levels in semiconductors by measuring changes of either capacitance [1,2] or current [3]. Common measurement regimes include either temperature scans or low temperature experiments, when only processes of carrier emission from deep levels are controlled.…”