Physical parameter extraction by inverse device modelling: Application to one- and two-dimensional doping profiling

Abstract

Semiconductor device simulations require valid physical input parameters for their results to be adequate. The technique of parameter extraction by error minimization has up till now almost exclusively been applied to analytical models for circuit simulations. A generalized application to the determination of material properties for device models is proposed, leading to the principle of inverse modelling. As an example application, the nondestructive determination of doping profiles from electrical measurements is discussed. A step profile is presented to show the reduced noise sensitivity of the inverse modelling method as compared to that of the traditional CV method; also, more accurate results are obtained because the abrupt depletion approximation is not required. As a second example, the complete profile in a Junction Charge-Coupled Device has been determined to illustrate the possibility of two-dimensional doping profiling. The application range of inverse device modelling is not limited to doping profiling; further application to MOSFET channel mobility determination is proposed. The advantages and disadvantages of inverse modelling as compared to tradiational methods are investigated.