Extraction of channel length and junction voltage in n+/n/n+ or n+/p/n+ polysilicon resistors

A method for extraction of channel length and junction voltage of poly-Si resistors is presented. Direct extraction of channel length can be performed for n⁺/n/n⁺ resistors operating in the nonlinear I-V regime. However, poly-Si resistors may have channel doping opposite to that of the source/drain doping. For this case, a method is presented for extraction of the current-dependent voltage drop across the drain n⁺/p junction. Importantly, this junction voltage drop can be an appreciable fraction of the drain-to-source bias and thus is important for correct analysis of n⁺/p/n⁺ resistors