Suppression of stress-induced leakage current after Fowler-Nordheim stressing by deuterium pyrogenic oxidation and deuterated poly-Si deposition

Reports on the effect of deuterium incorporation into gate oxide on stress-induced leakage current (SILC) under Fowler-Nordheim (F-N) electron injection. Deuterium atoms were introduced during the growth of the gate oxide by deuterium pyrogenic oxidation. A deuterated poly-Si film was also utilized as a gate electrode. The deuterated poly-Si gate electrode was deposited by deuterated monosilane (SiD₄) gas, as a substitute for hydrogenated monosilane (SiH₄) gas. The properties of the deuterated oxide were compared with those of deuterium-annealed oxide, i.e., the conventional method for deuterium incorporation into gate oxide. As a result, it was found that SILC after both polarities of F-N stressing was clearly suppressed by the use of both the deuterium pyrogenic oxide and the deuterated poly-Si gate. Experimental results for the depth profiles and thermal desorption characteristics of introduced-deuterium atoms, compared with the case of the deuterium annealing, indicated that both the deuterium incorporation not only into the Si/SiO₂ interface but also into bulk-SiO ₂ and the more stable chemical bonding of deuterium atoms are realized by deuterium pyrogenic oxidation