Boosting the Ionizing Radiation Tolerance in the Mosfets Matching by Using Diamond Layout Style

Abstract

There are a lot of initiatives to improve the devices matching (dog bone layout, common centroid layout, dummy devices, etc.). Another layout technique, not yet used by integrated circuits (ICs) companies, is the utilization of non-conventional layout styles (hexagonal, octagonal, ellipsoidal, etc.) for MOSFETs, thanks to the Longitudinal Corner Effect (LCE), Parallel Connection of MOSFETs with different channel Lengths Effect (PAMDLE) and Deactivation of Parasitic MOSFETs in Bird’s Beaks Regions (DEMPAMBBRE). In this context, this paper describes an experimental comparative study of the devices matching of Metal-Oxide-Semiconductor Field Effect Transistors (130 nm Silicon-Germanium Bulk), n-type (nMOSFETs) implemented with Diamond (hexagonal) and standard rectangular layout styles, regarding a sample of 189 transistors which were exposure to different X-rays ionizing radiations. Considering some relevant electrical parameters considered in this work, the results indicate that the Diamond layout style with $\alpha$ angle equal to 90° is capable of boosting by at least 40% the device matching in relation to one observed with standard (rectangular) MOSFET counterparts in irradiation environment, considering they present the same gate areas, channel widths and bias conditions. Therefore, the Diamond layout style can be considered another hardness-by-design (HBD) layout strategy to boost the electrical performance and ionizing radiation tolerance of MOSFETs.