High-pressure Hydrogen Annealing Research Articles

Enhanced Reliability and Performance of High-k MOSFET by Two-Step Annealing

The effect of high pressure (HP) H 2 /D 2 annealing and subsequent N 2 annealing, to enhance reliability, on hafnium-based high-k metal oxide semiconductor field effect transistor (MOSFET) has been studied. HP hydrogen annealing effectively passivates dangling bonds which in turn reduce the interface state density. Additional annealing in nitrogen ambient reduces threshold voltage shifts (ΔV th ) due to bias temperature instability and hot carrier injection. This improvement due to subsequent annealing might be related with the annihilation of hydrogen-related trapping sites from the high-k bulk. Since charge trapping is attributed mainly to dangling bonds at the interface and excess hydrogen species in the bulk of the high-k oxide, by optimizing annealing conditions, both reliability and performance of high-k MOSFETs are improved.

A thorough study of hydrogen-related gate oxide degradation in deep submicron MOSFET’s with deuterium treatment process

Experimental results are presented for gate oxide degradation under direct tunneling stress conditions using p- and n-MOSFET’s with gate oxides that are treated with high-pressure hydrogen and deuterium annealing. Device parameter variations as well as the gate leakage current depend on and are improved by high-pressure deuterium annealing, compared to corresponding hydrogen annealing. The precursor for oxide trap is probably created in the bulk of the gate oxide, which depends on hydrogen concentration levels, however its generation is not related with SiO 2/Si interface reaction that produces the released hydrogen. The treatment with deuterium instead of hydrogen in device fabrication provides a possible solution to reduce the generation of oxide-trap precursor within the gate oxide.