Search

Lithium-sulfur batteries (LSBs) have been considered as the future potential energy storage system with advantages of high energy density (2600 Wh kg-1), eco-friendliness and low cost. However, the poor conductivity and serious shuttle effects of polysulfides block their application. Herein, g-C3N4/carbon heterostructure on graphene nanosheet (PCNG) is constructed via phenyl-modified strategy and in-situ thermal polycondensation, which has a unique electron cloud distribution with excellent sulfur immobilization ability as well as good electroconductivity. As a result, Li-S cells with simple S/C cathodes and PCNG interlayers show a high initial capacity of 1192 mAh g-1 at 0.1 C, and an ultra-long lifespan with a slow capacity attenuation of 0.050% per cycle after 800 cycles. The cell with PCNG/PP separator also has a stable cycle performance at high area sulfur loading of 7 mg cm-2. These findings provide a new sight on functionalizing g-C3N4 for application in Li-S electrochemistry.

Welcome to G03: SiGe, Ge, and Related Compounds: Materials, Processing, and Devices 9! Take a moment to listen to welcome remarks from the lead organizer, Qizhi Liu.

An integrated p-i-n diode for use in SiGe BiCMOS technology applications has been developed. The device may be used into the MMW frequency range

We present the advances in Silicon Germanium Heterojunction Bipolar Transistor (SiGe HBT) and BiCMOS technology capabilities to address the emerging millimetre-wave (mmWave) applications. SiGe HBTs with fMAX performance reaching 350 GHz that are integrated with advanced CMOS and high-frequency passives is envisioned to allow better integration capability for mmWave applications. This capability of SiGe HBT BiCMOS technology is discussed relative to an InP HBT technology. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Polybenzimidazole (PBI)/polyimide (PI) and PBI/polyvinylpyrrolidone (PVP) blends were prepared. All of these polymers are suitable for acid doping as a matrix because of the existence of the N-heterocycle in the polymers, which can eventually be used as proton conductors. The miscibility of PBI/PVP blend is confirmed by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM), while the miscibility of PBI/PI is already reported in references. Temperature dependence of proton conductivity of acid doped PBI/PI and PBI/PVP blends are studied. As the temperature increases, proton conductivity of H3PO4 doped PBI/PVP blends increases. Temperature dependence of proton conductivity of the blends can still be fitted by a simple Arrhenius relation. The proton transport of the blend is similar to that of PBI. The methanol permeability of PBI/PI blends is also studied. Methanol permeability in PBI/PI, PI, and PBI membranes decreases with increasing methanol concentration. POLYM. ENG. SCI., 45:1395–1400, 2005. © 2005 Society of Plastics Engineers

Peak f T of 660GHz is reported for HBT f T doubler designs in IBM 90nm SiGe BiCMOS technology 9HP. This high performance f T doubler utilizes a longer HBT for output stage compared to the input stage HBT (length ratio 2:1) resulting in improved transconductance and lower thermal resistance. The impact of HBT layout on the circuit performance and trade-off between thermal resistance and f T is also investigated. f T doubler circuit can be used as a single transistor in several circuit applications like A/D converters and broadband circuits where higher performance is desired.

Impact of mutual thermal coupling on the performance of a single 90nm SiGe heterojunction bipolar transistor (HBT) due to the presence of power dissipating elements like other HBTs in near vicinity is presented in this paper. Mutual thermal resistance (Rth,mutual) has been computed as a function of spacing between the single HBT and a ring of HBTs surrounding the device. HBT structural design variations including device layout schemes, metal wire stack connected to the emitter, deep trench (DT) depth and emitter to DT spacing, for reduced self thermal resistance (Rth), have been explored in this paper. An updated thermal resistance model accounting for the heat flow through the metal wiring stack connected to the emitter is also reported.

High performance Schottky Barrier Diodes (SBDs) with cut-off frequency (fc) ~2.0 THz integrated into a 90nm SiGe BiCMOS technology for millimeter wave (mm-wave) applications are presented in this paper. To our knowledge, this is the highest reported fc for a SBD in a BiCMOS technology. The SBDs reported here have low reverse bias leakage with breakdown voltage of ~5V, and have been integrated in the base technology without the addition of any extra processing step. The affects of variation of critical process and device parameters - undoped silicon layer (n-epi) thickness, thermal cycle associated with deep-trench formation, cathode reach-through width, and anode area on device performance have also been investigated and are presented here.

Having two, or more, transistors with different values of f T and BV CEO provides flexibility to circuit designers in making tradeoffs of power and performance. The process complexity and resulting cost of fabricating these transistors on the same wafer is another important factor. Three different approaches for co-integrating high-performance and high-breakdown SiGe npn HBTs with minimal process deviation are presented herein. The work features a high-performance HBT with f T × BV CEO product of 500GHz-V and a high-breakdown HBT with over 430GHz-V integrated on the same wafer with one-mask deviation.

In this paper, we discuss a novel technique to reduce base resistance (R b ) and collector-base capacitance (C cb ) for higher F max in high-speed SiGe HBTs. In order to reduce C cb , we first located the origins of the different components of C cb through AC extraction. Then we utilized scanning capacitance measurements (SCM) to examine the shape of the collector-base depletion. We then propose a method to reduce the extrinsic C cb , namely by using reticle enhancement techniques to print a blocking oxide layer to inhibit boron outdiffusion. An additional benefit was the reduction of R b by reducing the base link resistance.

The total ionizing dose and laser-induced transient response of a new 4th generation 90 nm IBM SiGe 9HP technology are investigated. Total dose testing was performed with 63.3 MeV protons at the Crocker Nuclear Laboratory at the University of California, Davis. Transient testing was performed on the two-photon absorption system at Naval Research Laboratory. Results show that the SiGe HBTs are dose-tolerant up to 3 Mrad(SiO2) and exhibit reduced single event transients compared to earlier SiGe generations.

In this paper, we investigate the emitter resistance R e in SiGe HBTs with speeds up to 280GHz, using a U-shaped polysilicon emitter. We observed that R e increased with lateral scaling, thereby degrading f T . Although a negligible component in the past, in this experiment R e * C cb transit time delay is playing a more significant role in limiting f T . R e was modeled to explain the increase due to lateral scaling, and was shown to result from the plugging of the emitter opening by the emitter polysilicon. Furthermore, process experiments were conducted to investigate the effect of emitter polysilicon thickness, sidewall height, and emitter i-layer thickness.

In this paper we introduce, a state-of-the-art SiGe BiCMOS power amplifier technology that features two NPNs with 40 GHz / 6.0 V & 27 GHz / 8.5 V (fT - BVceo) respectively, a novel low inductance metal ground through-silicon-via (TSV), integrated on a low-cost 0.35 μm lithography node with 3.3 V / 5.0 V dual-gate CMOS technology and high-quality passives on a 50 Ω.cm substrate.

The paper presents a 0.13 mum SiGe BiCMOS technology for millimeter wave applications. This technology features a high performance HBT (fT = 300 GHz /fmax = 330 GHz) along with various newly developed millimeter wave features, such varactor, Schottky and p-i-n diodes and other back end of line passives

With the advancement of the fT/fMAX performance scaling of SiGe HBTs the breakdown voltage (BVCBO/BVCEO) reduces commensurately, causing design related concerns. It is important, therefore, that multiple fT/BVCEO devices be offered in the RF technologies to meet the varying needs of the communication products. Unlike the GaAs technologies, the SiGe BiCMOS technologies are capable of integrating various flavors of fT/BVCEO SiGe HBT devices at a technology node. In this work, we investigate the tradeoff in fT-BVCEO for advanced SiGe HBTs by various collector optimization schemes such as, subcollector dopant species and concentration, epilayer thickness, SIC and other layout techniques.