A CLOSED-LOOP EVALUATION AND VALIDATION OF A METHOD FOR DETERMINING THE SCATTERING LIMITED CARRIER VELOCITY IN MOSFETS

A “closed-loop” evaluation of a saturation transconductance (gsi) based method for determining the scattering limited carrier velocity (i\M) in enhancement MOSFET’s was performed with the use of a 2-D device simulator. Consistency in the extracted i\M over a wide range of gate oxide thickness (7), channel doping concentration, and bias condition was tested and verified. Also analyzed are the appropriate measurement condition, the significance of parasitic effect due to the source and drain resistances, applicability of the method used for compensating this parasitic effect, and the expected accuracy of the extracted r., under ideal conditions. A plausible explanation is provided for the inconsistency between i\M determined from gsi (0), the extrapolated transconductance, and r′c determined from the slope of I Xw-In (0)] ’ versus TN characteristics observed in the results of a published work. Also investigated is the cause for nonzero intercepts in the (0) |_l versus Tm characteristics noted in a previously published work. In addition, it is shown that the particularities of the mobility model used in the simulation-based evaluation have little bearing on the results of this investigation, and the conclusions of this study are basically valid. The #!,’,NI,-based method for extracting i\M has been applied to MOSFET’s fabricated with three vastly different technologies, and the experimental-based of electrons at 300 K ranges from 7.37 x 10” to 7.92 x 10 6 cm/s, which shows its independence of technology. © 1990 IEEE