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

3.4.2.3 Dependence on the Annealing Timeof PMA with GoldUpper ElectrodesThe influence of the time of PMA with gold upper electrodes wasalready described in section 3.4.1.3. It is conceivable that annealing timewould exert any influence on any electrical characteristics in the case of PMAwith gold upper electrodes same as the case of aluminum upper electrodes.Accordingly, the dependence on the annealing time for PMA with gold upperelectrodes was investigated. Figure 3-44 shows the C-V characteristicsdependent the time of PMA with gold upper electrodes. Annealing time wasexamined from 0 sec to 100 minutes. The results of As-deposition and PDAsamples were shown in same graph as well. In contrast with the case ofPMA with aluminum upper electrodes, it was found that there was almost nodifference in electrical characteristics by variety of annealing time in thecase of PMA with gold upper electrodes. To be precise, the value of EOTslightly decreased with decrease in annealing time as shown in Figure 3-45.And it was also found that the value of EOT considerably increased whenannealing time became longer from 0 second to 10 minutes. However, thedependence of VFB shift on annealing time was not confirmed in the case ofPMA with gold upper electrodes as shown in Figure 3-46.Capacitance (µF/cm 2 )21Au/La O / n-Si(100)/Al2 3 250 o C depo HF-lastAs-depo.& PMA 300 o Cspike to 100min.N ambient2Ideal V FBAu_As-depo.Au_PMA_N2_spikeAu_PMA_N2_1min.Au_PMA_N2_10min.Au_PMA_N2_100min.0-1 0 1 2Voltage (V)Figure 3-44: The C-V characteristics dependent the time of PMAwith gold upper electrodes- 68 -