One-by-one trap activation in silicon nanowire transistors

Flicker or 1/f noise in metal-oxide-semiconductor field-effect transistors (MOSFETs) has been identified as the main source of noise at low frequency. It often originates from an ensemble of a huge number of charges trapping and detrapping. However, a deviation from the well-known model of 1/f noise is observed for nanoscale MOSFETs and a new model is required. Here, we report the observation of one-by-one trap activation controlled by the gate voltage in a nanowire MOSFET and we propose a new low-frequency-noise theory for nanoscale FETs. We demonstrate that the Coulomb repulsion between electronically charged trap sites avoids the activation of several traps simultaneously. This effect induces a noise reduction by more than one order of magnitude. It decreases when increasing the electron density in the channel due to the electrical screening of traps. These findings are technologically useful for any FETs with a short and narrow channel.Comment: One file with paper and supplementary informatio

Electron-Shading Characterization in a HDP Contact Etching Process Using a Patterned CHARM Wafer

In this work, a CHARM-2 wafer with high aspect ratio resist patterns has been used to quantitatively I. Introduction To understand the origin of plasma-induced damage, useful plasma parameters such as floating potentials and J-V characteristics can be measured using the non-invasive CHARM method To study this effect, we have designed different resist patterns on a 200 mm CHARM™-2 wafer with an e-beam lithography. This allows to obtain realistic variable aspect ratio as high as 4, contrary to previous studie

Assessing the correlation between location and size of catastrophic breakdown events in high-K MIM capacitors

The connection between the spatial location of catastrophic breakdown spots occurring in metal-insulator-metal capacitors with a high-permittivity dielectric film (HfO 2 ) and their respective sizes is investigated. Large area structures (10 4 -10 5 μm 2 ) are used for this correlation assessment since, for statistical considerations, a large number of spots in the same device is imperatively required. The application of ramped or constant voltage stress across the capacitor generates defects inside the dielectric that result in the formation of multiple failure sites. High power dissipation takes place locally, leaving a permanent mark on the top electrode of the device. The set of marks constitutes a point pattern with attributes that can be analyzed from a statistical viewpoint. The correlation between the spot locations and their sizes is assessed through the mark correlation function and the method of reverse conditional moments. The study reveals that for severely damaged devices, there exists a link between the spot location and size that leads to a short range departure from a complete spatial randomness (CSR) process. It is shown that the affected region around each failure site is actually larger than the visible area of the spot. A structural modification of the dielectric layer in the vicinity of the spot caused by the huge thermal effects occurring just before the microexplosion might be the reason behind this extension of the damage

Accurate determination of flat band voltage in advanced MOS structure

International audienc

Accurate determination of flat band voltage in advanced MOS structure

International audienc

Determination of well flat band condition in thin film FDSOI transistors using C-V measurement for accurate parameter extraction

International audienceFor advanced gate stacks, effective work function (WFeff) and equivalent oxide thickness (EOT) are fundamental parameters for technology optimization. On FDSOI transistors, and contrary to the bulk technologies, while EOT can still be extracted at strong inversion from the typical gate-to-channel capacitance (Cgc), it is no longer the case for WFeff due to the disappearance of an observable flat band condition on capacitance characteristics. In this work, a new experimental method, the Cbg(VBG) characteristic, is proposed in order to extract the well flat band condition (VFB, W). This characteristic enables an accurate and direct evaluation of WFeff. Moreover, using the previous extraction of the gate oxide (tfox), and buried oxide (tbox) from typical capacitance characteristics (Cgc and Cbc), it allows the extraction of the channel thickness (tch). Furthermore, the measurement of the well flat band condition on Cbg(VBG) characteristics for two different Si and SiGe channel also proves the existence of a dipole at the SiGe/SiO2 interface

Full front and back split C-V characterization of CMOS devices from 14nm node FDSOI technology

session: Advanced Processes and CharacterizationInternational audienceIn this paper, a full front and back split C-V characterization of FDSOI devices and associated methodology to accurately extract the EOT (Equivalent oxide thickness) of the front and back (BOX) oxide as well as the channel thickness are presented for the first time

Strain-enhanced performance of Si-Nanowire FETs

International audienc

HOT ELECTRON RELIABILITY OF DEEP SUBMICRON MOS TRANSISTORS

Nous étudions la dégradation des performances des transistors MOS ultra-courts (0.3 µm - 0.6 µm) engendrée par l'injection de porteurs chauds. Ces dispositifs ont un canal N, une structure conventionnelle (non LDD) et ont été optimisés pour fonctionner à 3 V. Plusieurs types de contraintes out été analysés. Un suivi systématique des paramètres importants a été réalisé en cours de vieillissement, la dégradation étant ensuite évaluée par des méthodes de caractérisation fine. L'influence des tensions d'alimentation sur la durée de vie des dispositifs est étudiée. Ces résultats sont interprétés en tenant compte de l'extension de la zone de défauts et du taux de génération locale d'états d'interface.The hot electron induced degradation of fully optimized N-channel MOSFET's, having channel lengths in the range 0.3 µm - 0.6 µm, is systematically investigated. The created defects and their influence on the device performance are evaluated with very sensitive techniques and explained using 2D modelling. The device lifetime is analysed as a function of the biasing conditions. These results are interpreted by taking into consideration the extension of the defective region as well as the local generation rate of interface states