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Highly stable and reliable operation is absolutely required for GaN-based high-efficiency power switching devices and high-power RF AlGaN/GaN HEMTs. For the improvement of operation stability in such devices, in this paper, the surface control technologies will be addressed by introducing an ultrathin-Al-layer process, an electrochemical oxidation and a multi-mesa-channel structure with relevant technologies.
The prospect for the introduction of III-V semiconductors into the channel of n-type MOSFETs and thus replace Si with a high mobility material for 22 nm technology generation and beyond is examined in detail. The so-called implantfree (IF) III-V MOSFET architecture option is presented showing a fabricated n-type IF demonstrator suitable for scaling. We then focus on a prediction of the potential performance...
Response of Ta2O5 stacks with Al and Au gates to voltage stress at gate injection is studied by probing at various voltage/time conditions. The pre-existing traps govern this response, and the impact of gate-induced defects is stronger. Two processes, electron trapping at pre-existing traps and positive charge build-up, are suggested to be responsible for generation of stress-induced leakage current...
Linear and non-linear modelling of a novel ultra-low noise InGaAs/InAlAs pHEMTs have been used to design a low noise amplifier operating from 0.3 to 2 GHz. The LNA has ~ 0.4 dB NF across the whole frequency band, power gain of 26 dB at 1.4 GHz and IP3 of 14 dBm, making it a good candidate for the aperture array concept of the Square Kilometre Array (SKA) telescope, GSM, GPS, civil and military DAB.
This paper presents the design, fabrication and characterisation of InGaAs-InAlAs pHEMTs suitable for low frequency LNA designs. Transistors with variations in the supply layer thickness or indium concentration are designed to provide for a range of transfer characteristics. Very low levels of leakage, of order of 0.2 muA/mm, are demonstrated by these pHEMTs, which enables the implementation of large-geometry,...
The paper describes NMOS and PMOS translinear cell which multiplies the current signals and which can be used for the current-mode signal processing. The translinear cell consists of NMOS or PMOS transistors that are treated in the sub-threshold conduction region. In this region the transistors exhibit an exponential dependency of the drain current versus the gate voltage and thus the translinear...
In this article, we investigate the effect of a rapid thermal annealing (RTA) on electrical properties InAIN/GaN MOSHEMT with Al2O3 insulating film. On samples, we measured input, output and pulse characteristics. Consequently, a threshold voltage and an extrinsic transconductance was determined. A more dramatic influence of RTA was observed after annealing at 700degC. In this case, a reduction of...
Using numerical device simulation we investigated in detail the operational behavior of a cylindrical nanowire tunneling transistor (TFET) and the effect of quantum confinement on its characteristics, with a strong focus on the scalability of such devices. Among others, we discuss the potential device improvements by considering alternative materials for the gate-stack and the source region.
We have prepared metal/insulator/metal (MIM) structures with RuO2 bottom electrode and TiO2 dielectric film for advanced dynamic random access memory (DRAM) technology. RuO2 films were grown by metal organic chemical vapour deposition while TiO2 films were prepared by atomic layer deposition. RuO2 bottom electrode crystallizes in rutile structure and induces growth of rutile TiO2. Equivalent oxide...
Organic thin film transistors (OTFT) characteristics generally depend on organic semiconductor thin film growth conditions and the gate dielectric. Authors concerned with the basic properties of pentacene OTFT, where the gate dielectric consists of three different dielectric materials: SiO2 (HMDS treated), SiO2 covered with diacetylene SAM formed by the Langmuir-Blodgett method and SiO2 covered with...
AlGaN/GaN heterostructure field effect transistors with different gate recess depths have been fabricated using an ICP etch process. Subsequently, electrical DC characterization has been performed. The results have been compared with the theoretical predictions according to the simple charge control model, showing that for a given AlGaN/GaN structure there is an optimum thickness with respect to the...
The progress in the field of MOSFET devices was facilitated by the downscaling of their dimensions. To maintain device performance, the lateral layout was improved continually, but in recent years new device architectures as Ultra Thin Body and Multi Gate devices were discussed. Furthermore new materials were introduced as high-K gate dielectrics and metal gates. Today the advantages of strained silicon...
Reliability of the AlGaN/GaN HFETs was investigated by applying a short-time (70 min) off-state stress: the drain voltage was 50 V and the channel was pinched off. Significant decrease of the drain current at the stressing conditions was observed. Simultaneously, a decrease of the gate currents was found. On the other hand, the transconductance and threshold voltage did not changed with the stressing...
Three independent methods show clear evidence that pentacene layers grown on parylene C layer had better molecular microstructure compared to films grown on SiO2 surface. The electrical measurements confirmed these results and carrier mobility of 0.15 cm2 /Vs was obtained in OFET devices.
Thermal annealing was used to investigate traps at the surface of AlGaN/GaN HFETs and Al2O3/AIGaN/GaN MOSHFETs. The C-V and static output and transfer measurement yielded nearly identical characteristics for unannealed and annealed structures, regardless whether unpassivated or gate-oxide structures were used. A strong influence of the annealing on the gate leakage current was observed. The leakage...
Electrical properties of metal-oxide-semiconductor structures composed of MOCVD grown Ru or RuO2 metal gates, rf sputtered Ta2O5 oxide layers, and nitrided Si was investigated. The dielectric constant of Ta2O5 as extracted from capacitance-voltage characteristics was found to be 24 and 28 for Ru and RuO2 gated structures, respectively. Interfacial SiO2-like layer with a thickness of ~2 nm was observed...
We present a new modified approach in the forming of interdigital transducers (IDTs) on AlGaN/GaN heterostructure fully compatible with the process technology of HEMTs. The modified approach uses a shallow recess-gate plasma etching of AlGaN barrier layer in combination with "in-situ" SF6 surface plasma treatment under Schottky gate fingers of IDTs. It enables to excite surface acoustic...
Novel built-in current sensor structures based on selected electrophysical properties of a magnetic FET (MAGFET) is presented. The proposed sensor structures may be used for on-chip current testing in deep-submicron circuits with ultra low-voltage power supply. Their advantage is mainly in elimination of the undesired supply voltage reduction on the current monitor, commonly created by standard current...
The improved dc and microwave properties of 2 mum gate length AlGaN/GaN based HEMT structures were observed after applying of a novel approach in the forming of the Schottky gate interface. The new approach uses a shallow recess-gate plasma etching of AlGaN barrier layer in combination with "in-situ" SF6 surface plasma treatment under Schottky gate. A significant improvement in both the...
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