The Second Generation of Layout Styles to Further Boost the Electrical Performance of Analog MOSFETs

Abstract

© 2022, Brazilian Microelectronics Society. All rights reserved.Previous studies have shown that the first generation of layout styles composed by the Diamond (hexagonal), Octo (octagonal), and Ellipsoidal gate shapes for the imple-menting of the planar and three-dimensional Metal-Oxide-Semiconductor (MOS) Field Effect Transistors (MOSFETs) are capable of boosting their analog and digital electrical per-formances, ionizing radiation tolerances, and reducing the die areas used in comparison to those transistors designed with conventional rectangular layout styles. In order to further boost these features obtained by the use of the first generation of layout styles, one of elements of the second generation of layout styles for MOSFETs, entitled Half-Diamond, is being intro-duced. This new proposal is an evolution of the Diamond layout style, which is able to preserve the Longitudinal Corner Effect (LCE), the Parallel Connection of MOSFETs with Different Channel Lengths Effect (PAMDLE), and the Deactivation of Parasitic MOSFETs in Bird’s Beaks Regions (DEMPAMBBRE) effects promoted by the first generation. This layout style can also reduce the effective channel lengths of MOSFETs in comparison to those reached by the Diamond layout style. In this context, this work performs an experimental comparative study between the electric performances of MOSFETs implemented with the Half-Diamond, Diamond, and Conventional layout styles, considering they present the same gate areas, bias conditions, and the 180 nm Bulk CMOS ICs technology node. The experimental results show that the satu-ration drain current normalized by the aspect ratio and low-frequency open-loop voltage gain, in dB, of MOSFET implemented with the Half-Diamond layout style (HDM) are 17% and 3.5% higher, respectively, than those found in MOSFETs counterparts, designed with the conventional rectangular gate shape (CMs).