8.2 Optimization Results

Having defined all necessary models as well as the optimization experiment we are ready to submit our example to SIESTA. Figure 8.7 shows the GUI which allows to track the state of the optimization procedure. All the data which can be viewed by selecting items of this status tree are also available for off-line viewing. This means that one can monitor an optimization and its progress also by viewing it with a separate program. This is especially important if someone needs to track an optimization remotely using a network connection. Moreover, off-line monitoring is convenient if the optimization is performed in batch mode without a GUI. Batch operation can be necessary if the complete optimization is done remotely using a slow network connection.

Table 8.1 summarizes the initial settings of process parameters and their final values as result of the optimization procedure. The electrical parameters of device are summarized in Table 8.2.

The attempts of the optimization tool to improve the target are displayed in Figure 8.8. The parameters of the fabrication process are displayed in the left column of Figure 8.8 and on the very bottom of its right column. One can see from the history of the substrate current ibulk that the optimizer is able to successively improve the fabricated devices in terms of the substrate current, while the drive current ion is kept at its initial value due to the optimization constraint. The history of the substrate current (Figure 8.8, ibulk) shows that it is reduced by approximately 50% to $\mbox{$6.5\cdot{}10^{-5}$}~\mathrm{mA}$ compared to the initial value of $\mbox{$1.6\cdot{}10^{-4}$}~\mathrm{mA}$.