7 Conclusion



next up previous contents index
Next: 7.1 Suggestions for Future Up: Part II: Applications Previous: 6.4 Conclusion

7 Conclusion

In this dissertation, four TCAD framework task modules are introduced:

The development and implementation aspects of these tasks are discussed. The mathematical algorithms used are described with emphasis on their use and characteristics in a TCAD environment. Particular software considerations include a proposed uniform model representation which together with a client/server architecture facilitate the developement of the task code and its integration within VISTA.  

Applications of the task modules to the characterization of CMOS ULSI technology are described. A major contribution   of this work is the new technique for the determination of the two-dimensional doping profile of a MOSFET.   This inverse modeling method uses the nonlinear least-squares optimizer   to determine the coefficients of the B-spline and   tensor product spline functions that represent the one- and   two-dimensional profile variation from capacitance measurement.

The nonlinear optimizer is also used for the calibration of TCAD simulators to a manufacturing process. Three different examples illustrate this capability. A complete TCAD based characterization methodology that involves the use of the four task modules demonstrate the critical role of TCAD task in state-of-the-art technology development. This methodology   covers the process of generating analytical MOSFET models for circuit simulations based on nominal extracted doping profiles and a limited set of statistical device variables. A final application, namely a method for MOSFET gate length determination provides a further confirmation of the essential role TCAD tasks can play in submicron technology characterization   and development.





Martin Stiftinger
Tue Aug 1 19:07:20 MET DST 1995