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

3.4.3.2 Dependence on the Annealing Timeof PMA with PlatinumUpper ElectrodesThe dependence on the annealing time for PMA with platinum upperelectrodes was investigated same as aluminum and gold upper electrodes.Figure 3-55 shows the C-V characteristics dependent the time of PMA withplatinum upper electrodes. Annealing time was examined from 0 sec to 100minutes. The results of As-deposition and PDA samples were shown insame graph as well. Roughly speaking, there was almost no difference inC-V characteristics up to 10 minutes by a variation of the time of PMA.However, some changes of the characteristics such as slight VFB shift, adecrease of capacitance value or an appearance of hysteresis were observedin the case of PMA for 100 minutes. To be more precise, the values of EOTof PMA slightly decreased with an increase in annealing time up to 10minutes as shown in Figure 3-56. Moreover, the value of EOT of PDA waslower than the ones of PMA same as the case of aluminum upper electrodes.Figure 3-57 shows the plot of VFB shift dependent on annealing time. It wasfound that the VFB shift slightly recovered with increase in annealing time.And it was also found that PDA caused VFB to shift toward negative sidesame as the case of aluminum upper electrodes.2Pt/La O / n-Si(100)/Al2 3Capacitance (µF/cm 2 )1250 o C depo HF-lastAs-depo. & PMA 300 o Cspike to 100min.N ambient2Pt_PMA_300C_spike_N2Pt_PMA_300C_1min._N2Pt_PMA_300C_10min._N2Pt_PMA_300C_100min._N2Ideal V FB0-0.5 0 0.5 1 1.5 2 2.5Voltage (V)Figure 3-55: The C-V characteristics dependent the time of PMA- 78 -