Effect of Post Metallization Annealing for La 2 O 3 Thin Film

Figure 3-30 shows the plots of EOT dependent on the time of PMA.This graph also contains the plots of As-deposited and PDA sample depositedsimultaneously. It was found that the value of EOT almost did not changedependent on the time of PMA until 10minutes. When the annealing timereached 100 minutes, a slight increase of EOT was observed same as aincrease of hysteresis as already mentioned. However, it was also observedthat the value of EOT severely increased as compared with one of PDA.From a large number of experiments, it is found that the rate of the increaseof EOT after PMA compared to PDA is not same for each deposition on ourexperiment. The rate of the increase of EOT were about 20 ~ 50 % fromEOT of PDA. From this fact, it is conceivable that the same quality ofLa2O3 thin films could not have been deposited in our present experimentalsystem. From empirical knowledge, it is also found that the electricalcharacteristics practically tend to become better as the same La2O3 sourcewas used for long term. The considerations of the reason why PMA withaluminum increases EOT will be explained later.2.42.2EOT [nm]21.81.61.41.210 -1 10 0 10 1 10 2 10 3 10 4 As-depo.PDA_N2PMA_N2Annealing Time [Sec.]Figure 3-30: The plots of EOT dependent on the time of PMA- 56 -