A new AC measurement technique to accurately determine MOSFET constants

An ac measurement technique to accurately determine <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β₀ = μ₀CₒₓWeff/Leff</tex> , the mobility degradation coefficient Θ, and the drain-source resistance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RT = RS + RD</tex> is presented, and results are given for a PMOS transistor array with constant width (40 µm) and variable channel lengths (ranging from 0.8 to 4 µm). Because the proposed method does not require significant data reduction, it offers a number of advantages over previously published techniques. In addition, the method yields a refined value for the threshold voltage by curve fitting the measured and computed gate characteristics with V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> as a parameter. This procedure reduces the sensitivity of the technique to small errors made in a threshold-voltage measurement.