Hydrogen induced positive charge generation in gate oxides

Abstract

Articles you may be interested inHybrid titanium-aluminum oxide layer as alternative high-k gate dielectric for the next generation of complementary metal-oxide-semiconductor devices Appl. Phys. Lett. 86, 042904 (2005); 10.1063/1.1856137 Evaluation of nickel and molybdenum silicides for dual gate complementary metal-oxide semiconductor application Appl. Phys. Lett. 86, 022105 (2005); 10.1063/1.1849850Secondary ion mass spectrometry characterization of source/drain junctions for strained silicon channel metal-oxide-semiconductor field-effect transistors This article investigates the H 2 -anneal induced positive charge generation in the gate oxide of metal-oxide-semiconductor field-effect transistors fabricated by a submicron complementary metal-oxide-semiconductor process. A significant number (ϳ10 12 cm Ϫ2 ) of fixed and mobile positive charges are generated at 450°C. Properties ͑reactivity, electrical and thermal stability͒ of these positive charges are compared with the positive charges observed in the buried oxide of silicon-on-insulator devices. The differences in these two are investigated, in terms of their transportation time across the oxide, uniformity and sources of hydrogen. Attention is paid to the role played by boron in the generation and the possible connection between the positive species observed here and the defects responsible for the positive bias temperature instability. Efforts are made to explain the difference in reactivity between the H 2 -anneal induced positive species and the hydrogenous species released by irradiation or electrical stresses.

Mechanisms for generation of oxide trapped charges in ultrathin silicon dioxide films during electrical stress

“…However, hole trapping phenomenon alone cannot explain the positive charge trapping characteristics in the bulk of ultrathin SiO 2 . Rather, positive charge trapping in the bulk of ultrathin oxide can be best explained by the cumulative effects of hole trapping in as-fabricated traps possibly originated from bridging oxygen vacancies [1] and captured proton-induced overcoordinated oxygen centers [Si 2 @OH] + [6,9]. These proton-induced defects are most probably generated at the Si/SiO 2 interface, where they are ''stabilized'' by the strain that resides at the interface.…”

“…However, little work [6][7][8] has been done in understanding electrical stressinduced degradation of ultrathin SiO 2 in direct tunneling (DT) regime. Furthermore, the origin of positive oxide charge remains a controversy between proton-induced defect generation [1,6,9] and hole trapping [2,4] in as-fabricated traps. In the present work, it is found that electron trapping in SiO 2 film of thickness as low as 2.4 nm is suppressed during CVS with negative gate bias, a behavior contrary to thicker oxides as reported by DiMaria et al [1,2].…”

Instability and Defects in Gate Dielectric: Similarity and Differences Between Hf-Stacks and SiO2

“…For some SiO 2 , it has been reported that forming gas anneal at 450 o C or above can also induce positive charging (28)(29)(30). One way for enhancing the positive charging is to expose SiO 2 to a temperature of 1100 o C or higher (30).…”

“…Hydrogen enhances positive charging(30). For some Hf-stacks, the FG anneal has little effect on both poly-(a) and TaNgated (b) nMOSFETs.…”

“…Device-to-device variations of H 2 -induced positive charges after exposing 10.8 nm SiO 2 to FG at 450 o C for 460 min(30).…”