Effects of post-deposition annealing on the electrical propertiesand reliability of ultrathin chemical vapor deposited Ta2O5 films |
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| Authors: | Han L.K. Yoon G.W. Kwong D.L. Mathews V.K. Fazan P.C. |
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| Affiliation: | Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX; |
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| Abstract: | This paper reports the effects of post-deposition rapid thermal annealing on the electrical characteristics of chemical vapor deposited (CVD) Ta2O5 (~10 nm) on NH3-nitrided polycrystalline silicon (poly-Si) storage electrodes for stacked DRAM applications. Three different post-deposition annealing conditions are compared: a) 800°C rapid thermal O2 annealing (RTO) for 20 sec followed by rapid thermal N2 annealing (RTA) for 40 sec, b) 800°C RTO for 60 sec and c) 900°C RTO for 60 see. Results show that an increase in RTO temperature and time decreases leakage current at the cost of capacitance. However, over-reoxidation induces thicker oxynitride formation at the Ta2O5/poly-Si interface, resulting in the worst time-dependent dielectric breakdown (TDDB) characteristics |
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