Charge trapping and current-conduction mechanisms of metal-oxide-semiconductor capacitors with LaxTay dual-doped HfON dielectrics

Charge trapping and related current-conduction mechanisms in metal-oxide-semiconductor (MOS) capacitors with LaxTay dual-doped HfON dielectrics have been investigated under various post-deposition annealing (PDA). The results indicate that by LaxTay incorporation into HfON dielectric enhances electrical and reliability characteristics, including equivalent-oxide-thickness (EOT), stress-induced leakage current (SILC), and trap energy level. The mechanisms related to larger positive charge generation in the gate dielectric bulk can be attributed to LaxTay dual-doped HfON dielectric. The results of C-V measurement indicate that more negative charges are induced with increasing PDA temperature for the LaxTay dual-doped HfON dielectric. The charge current transport mechanisms through various dielectrics have been analyzed with current-voltage (I-V) measurements under various temperatures. The current-conduction mechanisms of HfLaTaON dielectric at the low-, medium-, and high-electrical fields were dominated by Schottky emission (SE), Frenkel-Poole emission (F-P), and Fowler-Nordheim (F-N), respectively. A low trap energy level (Phi(trap)) involved in Frenkel-Pool conduction in an HfLaTaON dielectric was estimated to be around 0.142 eV. Although a larger amount of positive charges generated in the HfLaTaON dielectric was obtained, the Phi(trap) of these positive charges in the HfLaTaON dielectric are shallow compared with HfON dielectric. 2010 Elsevier Ltd. All rights reserved.