Influence of Fin and Finger Number on TID Degradation of 16-nm Bulk FinFETs Irradiated to Ultrahigh Doses

This article investigates the fin- and finger-number dependence of the total ionizing dose (TID) degradation in 16-nm bulk Si FinFETs at ultrahigh doses. n- and p-FinFETs designed with different numbers of fins and fingers are irradiated up to 500 Mrad(SiO₂) and then annealed for 24 h at 100 °C. The TID responses of nFinFETs are insensitive to the fin number, as dominated by border and interface trap generation in shallow trench isolation (STI) and/or gate oxide. However, pFinFETs show a visible fin-number dependence with worst tolerance of transistors with the smallest number of fins. The fin number dependence may be related to a larger charge trapping in STI located at the opposite lateral sides of the first and last fins. In addition, both n- and p-FinFETs exhibit an almost TID insensitivity to the finger number. During the design of integrated circuits, the TID tolerance of electronic systems can be enhanced by preferably using transistors with a higher number of fins than fingers.

I. Introduction

To extend the discovery potential of cutting edge research in the field of high-energy physics, the large hadron collider (LHC) at Conseil Européen pour la Recherche Nucléaire (CERN) will be soon upgraded to increase its integrated luminosity by a factor of 10. It is expected that the high-luminosity LHC will expose its electronics to ultrahigh total ionizing doses (TIDs) up to 1 Grad(SiO₂) over ten years of operation. A CMOS Si-based 16-nm FinFET commercial technology is being evaluated as a promising candidate for improving the performances of the tracker readout electronics of a toroidal LHC apparatus (ATLAS) and compact muon solenoid (CMS) experiments [1], [2].