4.10 Conclusion

In conclusion, a nondestructive technique for MOSFET 2D profile determination was presented. The method does not require any difficult sample preparation and uses measurements easily performed during process characterization. It fills an important gap in the available process metrology tools. As shown, the results are very encouraging, however, further development of the technique is still needed. In particular, the following areas deserve more attention:

• Development of an algorithm for selecting the appropriate number of TPS knots and their locations similar to the one described for the one-dimensional case in Section 4.5.1.
• A more rigorous and quantitative study of the resolution and accuracy of the method is still needed.
• A comparison between the profiles extracted using the inverse modeling technique and profiles determined by direct measurements, when possible, could serve as a cross validation check.
• Finally, the extension of the method to include other sources of electrical data, such as subthreshold current measurements, is to be investigated as a way to improve its resolution beyond what is possible when relying uniquely on capacitance data.