1530-4388 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TDMR.2019.2916230, IEEE Transactions on Device and Materials Reliability TDMR-2019-03-0061-SS-IIRW.R1 Copyright © 2019 IEEE. Personal use of this material is permitted. However, permission to use this material for any other purposes must be obtained by sending a request to pubs-permissions@ieee.org Abstract— This paper discusses the impact of self-heating (SH) on ring-oscillator (RO) reliability and its correlation to hot carrier (HC) degradation. We show that HC degradation modulation due to SH is only significant for logic PFETs at highly accelerated DC conditions. We show that these SH effects on HC are greatly reduced at moderate acceleration. By stressing the ROs at extreme conditions, we show that the SH impact on HC does not affect RO degradation. Index Terms— Self-heating, ring oscillator, hot carrier injection, reliability, heat sensor. I. INTRODUCTION elf-heating has been reported as a rising concern in three- dimensional structures such as bulk/SOI FinFETs [1-3]. The confined heat is expected to accelerate some of the transistor reliability mechanisms, particularly HC degradation [4-6]. A correction method has been proposed to account for self-heating effects (SHE) when modeling HC degradation [5]. However, the extent of SHE on HC at moderate acceleration levels is yet to be addressed. On the other hand, SH and HC degradation are supposed to be reduced during AC stress [5]. However, the extent of SH effects on HC in logic circuits, such as Ring-Oscillators (RO), needs to be quantified. In this paper, we evaluate SHE on HC for different device densities, at different stress levels (DC) and we show that the HC difference due to SHE is greatly reduced at moderate acceleration. Additionally, we measured the self- heating of different RO designs with different densities and correlated to RO degradation. We show that the heat Submitted for review March 1 st , 2019. P. Paliwoda, T. Nigam, K. Nagahiro, S. Cimino, M. Toledano-Luque, L. Pantisano and B. Min are with GLOBALFOUNDRIES INC., 400 Stone Break Road Extension, Malta, NY, 12020, USA (e-mail: peter.paliwoda@globalfoundries.com; tanya.nigam@globalfoundries.com; kurt.nagahiro@globalfoundries.com;salvatore.cimino@globalfoundries.com; maria.toledanoluque@globalfoundries.com,luigi.pantisano@globalfoundries.c om and byoung.min@globalfoundries.com). Z. Chbili is with Intel corp., 1900 Prairie City Road, Folsom, CA, 95630, USA (e-mail: zakariae.chbili@intel.com), A. Kerber formerly with GLOBALFOUNDRIES INC., 400 Stone Break Road Extension, Malta, NY, 12020,USA (e-mail: Andreas.Kerber@IEEE.org) D. Misra is with the Electrical and Computer Engineering Department, New Jersey Institute of Technology Newark, NJ, 07102, USA (e-mail: dmisra@njit.edu). generated by the different density ROs is negligible and that their degradation is identical. II. EXPERIMENTAL SETUP Dedicated ROs were designed in 14-nm bulk FinFET technology to measure self-heating in logic circuits. Several RO designs were implemented with different densities (number of fins, number of fingers) and different number of stages (13 and 101 inverting stages having different oscillating frequencies). Metal sensor with Kelvin contacts was placed immediately on top of the ROs (first metal layer) to allow measurement of RO self-heating (Fig. 1). The SH measurement methodology used in this study was described in [6,7]. Additionally, discrete logic and IO NFET/PFET FinFETs were designed to measure SH and HC at DC conditions for 4 different architectures (Fig. 2) with increasing densities but same total width (same drain current). This is to ensure that the hot carrier degradation is not modulated by different drain currents and fair comparison is given by applying same power dissipation to each device, however the active region (RX) will experience different SH level depending on Fin count density. Self-heating effects on Hot carrier degradation and its impact on logic circuit reliability P. Paliwoda, Z. Chbili, Member, IEEE, A. Kerber, Senior Member, IEEE, T. Nigam, K. Nagahiro, S. Cimino, Member, IEEE, M. Toledano-Luque, L. Pantisano, B. Min, Senior Member, IEEE and D. Misra, Senior Member, IEEE S Fig. 1. Illustrative figure showing the Ring-Oscillator layout design (2Fins/RX, 2 Fingers shown here) with metal (M1) temperature sensor with Kelvin contacts. RO Gate Drain Contact RX Fins Gate Contact Metal 1st Metal 1st Kelvin Sensor