9.3.3 Deriving a Metric for the Match

The network-model described by Example 9.4 and depicted in Figure 9.6 quantifies the match for the transfer (I_D/V_G), and output curves (I_D/V_D) for the NMOS device produced by the simulation-flow-model designed before. It uses MINIMOS-NT for this purpose, which is encapsulated by a simulation-flow-model ("device.mod"). MINIMOS-NT offers a nice feature to read the sequence of operating points to be simulated, which constitute a desired I/V-curve, from a preexisting I/V-curve. Since this model has to compare these curves to the measured I/V-curves, we use the settings of the measurements to control the MINIMOS-NT device simulator. Thus, we derive simulated I/V-curves which are structurally identical to their measured equivalent.

The actual comparison is done by the curve-calculator-model ("curve-calc.mod") described by Example 9.3. It defines the measure of match as

$$m = \left\{ \begin{array}{ll} \frac{I_{meas} - I_{sim}}{I_{s... ...cdot 100 \mbox{\% } & I_{sim} > I_{meas} \end{array} \right.$$

which delivers values between $[ +100\mbox{\%}, -100\mbox{\%}]$. The output of the curve-calculator-model is a curve which contains this measure of match for each operating point of the measured curve.

As next step we convert this structured representation of the match into the flat representation of a vector of floating point numbers. We do this by means of the curve-to-vector-models labeled flatten-idvg, and flatten-idvd. These models convert the curve column known as Id into a vector. Finally, we concatenate these two vectors into a single one by means of a merge-vector-model, which is labeled merge and thus obtain the result of the network-model at the output port named match.