Experimental determination of threshold voltage shifts due to quantum mechanical effects in MOS electron and hole inversion layers

The authors report for the first time, accurately extracted experimental data for the threshold voltage shift (/spl Delta/V/sub T/) due to quantum mechanical (QM) effects in hole inversion layers in MOS devices, Additional experimental results are presented for QM effects in electron inversion layers. Compared to classical calculations, which ignore QM effects, these effects are found to cause a significant increase in the threshold voltage (/spl sim/100 mV) in MOSFET devices with oxide thicknesses and doping levels anticipated for technologies with gate lengths /spl les/0.25 /spl mu/m. /spl Delta/V/sub T/ has been determined from experimental devices with doping levels ranging from 5/spl times/10/sup 15/-1/spl times/10/sup 18//cm/sup 3/, and recently developed theoretical models are found to agree well with the results. In addition, an innovative technique using a two-dimensional (2-D) device simulator in conjunction with the experimental capacitance-voltage (C-V) characteristics has been developed in order to more accurately extract various physical parameters of the MOS structure.