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This work provides a detailed study of 28 nm fully-depleted silicon-on-insulator (FD-SOI) planar ultra-thin body and BOX (UTBB) MOSFETs for high frequency applications. All parasitic elements such as the parasitic gate and source/drain series resistances, total capacitances are extracted and their effects on RF performance are analyzed and compared with previous work on similar devices. Two main RF figures of merit (FoM) such as the current gain cut-off frequency ( f T ) and the maximum oscillation frequency ( f max ) are determined. It is shown that f T of ∼280 GHz and f max of ∼250 GHz are achievable in the shortest devices. Based on the extracted parameters, the validation of the small-signal equivalent circuit used for modeling UTBB MOSFETs is investigated by comparing simulated and measured S -parameters.

In this work self-heating and its effect on analogue device parameters are compared in 28 nm technology bulk and FDSOI MOS devices. It is shown that for self-heating characterisation in advanced MOSFETs the RF extraction technique is more suitable than the pulsed I – V . It is found that the thermal resistance is ∼3.4 times higher and the temperature rise is ∼2.5 times higher in 28 nm gate length FDSOI than in bulk. However, in spite of stronger self-heating, FDSOI devices outperform bulk over a wide frequency range. Moreover, device parameters degradation with temperature is attenuated in FDSOI transistors.

This work presents an in-depth wide-frequency band assessment of 28 nm FDSOI MOSFETs for analogue and RF applications. The focus is mainly on such figures of merit (FoM) as the transconductance gm, the output conductance gd, the intrinsic gain Av and the cut-off frequencies fT and fmax. Firstly, 28 nm FDSOI MOSFETs are compared with other advanced devices and are shown to outperform them. Secondly, gm–Av analogue metric is demonstrated to be affected by operation frequency. Small-signal parameters variation is limited and dominated by self-heating effect. This is in contrast to the first generation of ultra-thin body and BOX devices without a ground plane where coupling through the substrate has a considerable effect. Thirdly, the self-heating effect is analysed and shown to be smaller than previously predicted by simulations for such devices. Fourthly, it is shown that fT of 280 GHz and fmax of 250 GHz are reachable in the shortest devices. These values are compared to those of the first generation of UTBB devices through the effect of parasitic elements.

This paper describes a complete process/design co-optimization methodology based on Fully Depleted SOI (FDSOI) technology. A process optimization is detailed through significant effective capacitance reduction, in order to optimize jointly frequency/leakage ratio and high frequency performances. In this objective, an efficient and low cost offset-spacers morphology has been designed to achieve maximum performance benefits. Both digital, analog and RF performances are exposed, and compared to 28LP gate-first technology. We evidence that FDSOI brings energy efficiency digital and AMS/RF breakthrough for IoT.

International audience; The hot carrier (HC)-induced traps in nanoscale fully depleted ultrathin body and buried oxide nMOSFETs are investigated by low-frequency noise (LFN) measurements in the frequency and time domains. The measured noise spectra are composed of 1/f and Lorentzian-type components. The Lorentzian noise is due to either generation-recombination noise or random telegraph noise (RTN). Based on the LFN results, the effect of the HC stress on fully depleted silicon-on-insulator MOSFETs is investigated after short- and long-time stress. The capture and emission time constants responsible for the RTN noise were calculated as the average duration time of the high/low drain current state, respectively. Analysis of RTN traps detected in fresh and HC-stressed devices indicates that the RTN amplitude is uncorrelated to the trap time constants, i.e., the impact of the trap depth from the interface is masked by that of the trap location over the channel. The overall results lead to an analytical expression for the RTN amplitude, enabling to predict the RTN changes from the subthreshold to the above-threshold region.

Vmin measurements in 28nm FDSOI technology on 128Mb SRAM bitcells from −40°C to 125°C are reported in this paper. Adding the silicon ageing behavior and the process variability, we have developed a complete model and demonstrated end-of-life SRAM Vmin of 0.6V and 0.5V on 20Mb with 0.120µm2 and 0.152µm2 bitcells, respectively. This is the first report of a such extensive SRAM Vmin assessment at the 28nm node. The construction of write limited bitcells, combined with write assist design technique, was found to be the most efficient way to achieve ultra low Vmin in 28nm FDSOI technology. In addition, Vmin retention below 0.4V is demonstrated in 0.120µm2 bitcells, leading to the enablement of ultra-low leakage bitcells with 2pA/cell in retention mode.

We present a 65nm RF SOI CMOS technology, targeted as Low Power (LP) to serve mobile applications. The integration has been made on High Resistive (HR) back substrate 300mm SOI wafers from SOITEC to improve performances in high frequency range, compared to bulk [1, 2]. For the first time, low leakage SRAM (Isb< 10pA at 0.9V, 25{degree sign}C, for 0.62µm2 and 0.52µm2 cells) are integrated on these HR wafers, and the paper reports a 30% power reduction in operation for a given maximum speed, compared to similar SRAM design on bulk. Furthermore, we have demonstrated a 21% measured power-delay product reduction compared to bulk, at 125{degree sign}C, on loaded ring oscillators.

This work presents a comparison of parasitic elements (capacitances and resistances) in a view of their effect on RF Figures of Merit (FoM) in 28 nm fully-depleted silicon-on-insulator (FD SOI) ultra-thin body and buried oxide (UTBB) MOSFETs and their Bulk counterparts. Complete set of small-signal equivalent circuit elements (both “intrinsic”, i.e. device related and “extrinsic”, i.e. parasitic) are extracted from S-parameters measurements in a frequency range up to 40 GHz. It is shown that detrimental/harmful effect of parasitics, particularly capacitances, is stronger in 28 nm bulk technology compared to 28 FD SOI.

session poster; International audience; The HC degradation of nanoscale FD-SOI n-MOSFETs has been investigated under the worst bias stress conditions (Vds,stress = Vgs,stress). At high stress voltages the hot carriers injected into the gate dielectric are the main degradation mechanism, superseding the interface degradation. The proposed degradation mechanisms are supported with the interface and gate dielectric trap properties extracted from LFN measurements.

session poster; International audience; A thorough investigation and statistical analysis of the low-frequency (LFN) and random telegraph noise (RTN) in 28 and 14nm FD-SOI CMOS transistors is presented, for the first time. It is shown that the 14nm technology node is improved in terms of threshold voltage fluctuations when compared to the 28nm one. A new analysis method that directly probes the RTN presence is also proposed. Finally, the LFN/RTN impact on the device dynamic variability is presented through CADENCE design suite circuit simulations.

A complete 65 nm CMOS platform, called LP/GP Mix, has been developed employing thick oxide transistor (IO), Low Power (LP) and General Purpose (GP) devices on the same chip. Dedicated to wireless multi-media and consumer applications, this new triple gate oxide platform is low cost (+1mask only) and saves over 35% of dynamic power with the use of the low operating voltage GP. The LP/GP mix shows competitive digital performance with a ring oscillator (FO = 1) speed equal to 7 ps per stage (GP) and 6T-SRAM static power lower than 10 pA/cell (LP). Compatible with mixed-signal design requirements, transistors show high voltage gain, low mismatch factor and low flicker noise. Moreover, to address mobile phone demands, excellent RF performance has been achieved with F T = 160 GHz for LP and 280 GHz for GP nMOS transistors.

This paper demonstrates the 28nm ultra-thin body and buried oxide (UTBB) FD-SOI high-density (0.120µm2) single p-well (SPW) bitcell architecture for the design of low-power wide voltage range systems enabled by back-bias adjustment. The results from a 140kb programmable dynamic SRAM characterization test module provide both information about location and cause of failures as well as power and performance by mimicking system operating conditions over a wide supply voltage range. A 410mV minimum operating voltage and less than 310mV data retention voltage with a leakage current close to 100fA/bitcell are measured. Improved bitcell read access time and write-ability through back-bias are demonstrated with less than 5% of stand-by power overhead.

This work provides a detailed study of 28 nm fully-depleted silicon-on-insulator (FD SOI) ultra-thin body and buried oxide (BOX) (UTBB) MOSFETs for high frequency applications. RF figures of merit (FoM), i.e. the current gain cut-off frequency (f T ) and the maximum oscillation frequency (f max ), are presented for different transistor geometries. The parasitic gate and source/drain series resistances, as well as capacitances and their effect on RF performance are analyzed.

Enabling high speed SRAM operation at low voltage is typically limited by variability and low device drivability. Most of the reported low-voltage SRAM bitcells show significant area penalty and low performances. This paper proposes a Mixed-Single Well (MSW) 8T SRAM bitcell, which takes advantage of wide back bias voltage range capability of ultra-thin body and box (UTBB) FD-SOI technology The bitcell is evaluated in 28nm using the read-after-write (RAW) dynamic metric which overcomes the limitations of standard readability (RA) and writeability (WA) approaches. It is demonstrated that body biasing tuning enables operation of the proposed bitcell at approx. 5.6s at 0.4V with over 100MHz.

Inter-die variability of analog figures of merit of ultra-thin body and buried oxide (UTBB) FDSOI MOSFETs was studied in a wide frequency range. We demonstrate that variability in the entire frequency range is small and does not exceed 5%, which is considerably less than in previously published results on SOI FinFETs. An effect of frequency on the analog figures of merit variability is discussed and preliminary explanation is proposed.

This work presents an in-depth wide-frequency band assessment of 28 nm FDSOI MOSFETs for analogue and RF applications. The focus is mainly on such figures of merit (FoM) as the transconductance g m , the output conductance g d , the intrinsic gain A v and the cut-off frequencies f t and f max . Firstly, 28 nm FDSOI MOSFETs are compared with other advanced devices and are shown to outperform them. Secondly, g m -A v analogue metrics is demonstrated to be affected by operation frequency. Small-signal parameters variation is limited and dominated by self-heating effect. This is in contrast to the first generation of ultra-thin body and BOX devices without a ground plane where coupling through the substrate has a considerable effect. Thirdly, the self-heating effect is analysed and shown to be smaller than previously predicted by simulations for such devices. Fourthly, it is shown that f t reaches ∼270 GHz in the shortest devices.

In this paper, we study how to boost the performance of FDSOI (Fully-Depleted Silicon On Insulator) devices with High-K and Single Metal gate by using the combination of Ultra-Thin Buried Oxide (UTBOX), Ground Plane (GP) and local back biasing integrated with our hybrid process. The interest of local back biasing is highlighted in term of threshold voltage VT modulation and power management study on the 45 nm 0.374 μm2 bitcells and on the ESD functionality as compared to bulk technology.

This work highlights the way to optimize the speed/power performance of the planar FDSOI technology at the 28nm node and beyond. The combination of gate length shrink and spacerO increase leads to 13% delay decrease and 15% dynamic power saving at same speed through capacitance reduction. It demonstrates that, as far as the access resistance penalty is kept reasonably low, increasing the spacerO is highly efficient to boost AC performance in FDSOI.

Unique features of the 28nm ultra-thin body and buried oxide (UTBB) FDSOI technology enable the operation of SRAM in a wide voltage range. Minimum operating voltage limitations of a high-density (HD) 6-transistor (6T) SRAM can be overcome by using a single p-well (SPW) bitcell design in FDSOI. Transient simulations of dynamic failure metrics suggest that a HD 6T SPW array with 128 cells per bitline operates down to 0.65V in typical conditions with no assist techniques. In addition, a wide back-bias voltage range enables run-time tradeoffs between the low leakage current in the sleep mode and the short access time in the active mode, making it attractive for high-performance portable applications.

International audience; Low-frequency (LF) noise has been studied on 28 nm FDSOI devices with ultra-thin silicon film (7 nm) and thin buried oxide (25 nm). A strong dependence of the noise level on the combination of the front and back biasing voltages was observed, and justified by the coupling effect of both Si/High-K dielectric and Si/SiO2 interface noise sources (channel/front oxide and channel/buried oxide), combined with the change of the Remote Coulomb scattering. From comparisons of the experimental and simulation results, it is shown that the main reason of this dependence is the distance of the charge distribution centroid from the interfaces, which is controlled by both front and back-gate bias voltages, and the way this distance affects the Remote Coulomb scattering coefficient a. A new LF noise model approach is proposed to include all these effects. This also allows us to assess the oxide trap density values for both interfaces.

In this work, we report on the integration of 30nm gate length CMOS devices fabricated using laser spike annealing (LSA). Considerably improved short channel effects and drive current (+10% Ion at constant Ioff for NMOS) are demonstrated on samples using LSA. Excellent IonIoff characteristics (Ion = 940 muA/mum Ioff = 200 muA/mum for NMOS and Ion = 390muA/mum Ioff = 50 nA/mum for PMOS at Vdd = 1 V) are measured that are at the leading edge of the state of the art. Moreover, an enhanced dynamic behavior (-6% in ring oscillator delay) and improved characteristics of high density SRAM bit-cells (+24% Icell for the same 1sb) are reported. These results demonstrate the potential of LSA in the perspective of 30 nm device integration of a 45 nm bulk CMOS platform

This work highlights the realization and 0.248/spl mu/m/sup 2/ to 0.334/spl mu/m/sup 2/ SRAM bit-cells with conventional bulk technology based on 19/spl Aring/ CET SiON gate oxide, poly-silicon gate electrode, and mobility enhancement techniques for both nMOS and pMOS. High density critical lithography levels have been exposed with e-beam direct writing thus contributing to the overall cost-effectiveness of the technology.

This work shows the benefits of using plasma nitrided gate oxide which supports the gate leakage requirements for 65 nm platform development. Electrical data shows gate leakage to be reduced by half a decade compared to conventional NO processing with Ioff at 3nA/um, Vdd=0.9 V for 65 nm general purpose requirements. Extensive device characterization of the plasma nitride process is presented where the reduction in gate leakage offers benefits in terms of a 4/spl times/ reduction in static power, a 6% reduction in dynamic power consumption, comparative analog performance and improved reliability.

This work highlights a 65 nm CMOS technology platform for low power and general-purpose applications. A 6-T SRAM cell size of 0.69 /spl mu/m/sup 2/ with a 45 nm gate length is demonstrated. Electrical data of functional SRAM bit-cell is presented at V/sub dd/=0.9 Volt using a conventional nitrided gate oxide dielectric. A comparison between offset spacer and PLAsma Doping (PLAD) is made for the transistor characteristics with very promising V/sub th/-L/sub d/ and V/sub th/-W/sub d/ profiles measured. Lithography employed a combination of both optical lithography and e-beam imaging. The BEOL integration used a conventional low K dielectric with copper metallization.

A 65nm CMOS platform employing General Purpose (GP) and Low Power (LP) devices and 0.5 /spl mu/m/sup 2/ 6T-SRAM bit-cells was developed using both conventional design and low cost CMOS process flow incorporating a strained silicon solution. Fully working 0.5 /spl mu/m/sup 2/ bit-cells with 240mV of SNM and 35 /spl mu/A of cell current at 1.2V operation were obtained. The GP transistor drive currents of 875 /spl mu/A/ /spl mu/m and 400 /spl mu/A/ /spl mu/m for NMOS and PMOS respectively are obtained at V/sub dd/ = 1V, Ioff = 100nA/um. Using the same CMOS flow, 65nm analog transistor parameters are derived for the first time, showing Vt matching (Avt=2.2mV. /spl mu/m) and analog voltage gain factor (G/sub m//G/sub d/>2000 for L = 10 /spl mu/m) at the leading edge for this process technology. NBTI criteria at 125/spl deg/C for both LP and GP transistors are presented and characterized at overdrive conditions.

This paper presents a complete 90nm CMOS technology platform dedicated to advanced SoC manufacturing, featuring 16/spl Aring/ EOT-70nm transistors (standard process) or 21/spl Aring/-90nm transistors (Low Power process) as well as 2.5 or 3.3V I/O transistors, copper interconnects and SiOC low-k IMD (k=2.9). The main critical process steps are described and electrical results are discussed. Moreover, using advanced lithographic tools, fully functional 1 Mbit SRAM instances, based on a highly manufacturable 6T 1.36/spl mu/m/sup 2/ memory cell, have been processed. The cell is detailed and its features, both electrical and morphological, are discussed.

In this paper, we demonstrate for the first time full integration of highly performant NMOS and PMOS silicon-on-nothing (SON) devices into circuits. We demonstrated fully functional SRAMs cells with very good yield, showing static noise margin (SNM) of 175mV and write margin (WM, stable "read 0") above 500mV. The optimized SON devices show performance for NMOS and for PMOS that is among the best published data (with drive current up to 1100/350/spl mu/A//spl mu/m for 138/20nA//spl mu/m I/sub off/ for NMOS and PMOS devices respectively @V/sub dd/=1.2V, I/sub ox/=16A). Finally, we present also the implementation of the SON process into a new "localized SOI" architecture on bulk. This new and simplified SON process is also demonstrated by fully operational SRAM cells.

This work investigates experimentally the non-linearities of FDSOI MOSFETs from DC to RF frequencies. The effect of the back-gate bias on non-linearity of the device is studied by means of 2nd and 3rd harmonic distortions (HD2 and HD3) extracted from dc I-V curves as well as from large-signal RF measurements using 1-dB and IP3 points. It is shown that the non-linearity is reduced by applying a positive back-gate bias. The reasons for this reduction are increasing of “effective body factor” and lesser mobility degradation with increase of the positive back-gate bias.