A Comprehensive Benchmarking Method for the Net Combination of Mobility Enhancement and Density-of-States Bottleneck

초록

In this letter, we propose a comprehensive benchmarking method to simultaneously address mobility enhancement and density-of-states bottleneck in advanced field-effect-transistors (FETs) with novel high-mobility (high-mu) channel materials, where we focused on conventional covalent bonding semiconductors with pure and partially ionic character. This method relies only on the measured extrinsic transconductance of a long-channel FET in the saturation regime together with the source resistance, yielding the product of the effective mobility (mu eff) and effective gate capacitance (C-g_eff). We tested this method in InxGa1-xAs quantum-well high-electron-mobility transistors (HEMTs) with various indium mole fractions, such as 0.53, 0.7, 0.8 and 1, aswell as in Si n-FETs. We found that the InxGa1-xAs HEMTs with mu eff over 10,000 cm(2)/V center dot s at 300 K provided more than 20 times greater mu(eff)x C-g_eff than Si n-FETs. More specifically, the product initially improved as x increased, then showed a peak value of 10,300 mu F center dot V-1 center dot s(-1) at x of around 0.8, and degraded slightly beyond that composition. To verify the validness of the proposed method, we separately measured and analyzed C-g_eff and mu(eff) using the split-CV technique, showing excellent agreement with the ones from the proposed method.

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