Experimental Investigation of RF Noise Performance Improvement in Graded-Channel MOSFETs

Abstract

In this paper, measured RF noise performance of graded-channel metal-oxide-semiconductor (MOS) transistors (GCMOS - also named laterally asymmetric channel transistors) shows impressive reduction in minimum noise figure ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NF</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> ) as compared to classical MOSFET transistors (with the same gate length <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Lg</i> = 0.5 mum). The reason is proven to be because of the higher noise correlation coefficient ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> ). GCMOS also shows lower sensitivity to extrinsic thermal noise as compared to classical MOSFET. Moreover, it is demonstrated that the use of 0.5- mum-gate-length GCMOS gives a competitive RF noise performance as compared to 0.25-mum-gate-length classical nMOS transistors.