High Frequency Transistors Research Articles

Establishing On-Wafer Calibration Standards for the 16-Term Error Model: Application to Silicon High-Frequency Transistor Characterization

Establishing On-Wafer Calibration Standards for the 16-Term Error Model: Application to Silicon High-Frequency Transistor Characterization

OSCILADOR DE MICRO-ONDAS COMO FONTE DE SINAL

This work presents the development of a prototype of a microwave oscillator with a fixed frequency, around 3 GHz, with microstrip lines, using a high frequency and low noise bipolar transistor, through the scattering parameters S, with the aim of support the practical activities developed in the RF laboratory of the electrical engineering course at IFSUL. Computational tools are used to develop the equations for the conversion of the scattering parameters, for the impedance matching calculations, for the fabrication of the microstrip lines and for the transistor polarization. Finally, two prototypes are built and the results are presented. The prototypes worked properly, highlighting the one designed with the aid of a computational tool.

Investigation of the Influence of the Purity of the Silicon Surface on its Wettability

Silicon is the basic material of microelectronics. It is made of rectifier, pulsed, microwave diodes, low frequency and high frequency, powerful and low-power bipolar transistors, field-effect transistors, charge-coupled devices. Silicon manufacturing the majority of diodes and thyristors. Silicon is widely used for the production of photosensitive devices: photodiodes and phototransistors. In addition, the silicon used to manufacture solar panels. Therefore, the study of the properties of silicon is relevant. In this study we investigated the influence of small doses of sodium chloride in water at an angle of draining the water droplets from the surface of the silicon. Surface wettability was determined by the following method. The sample was applied a drop of water of constant volume and inclination of the sample was recorded, the angle θ at which the drop began to drain from the surface found that small doses of NaCl in water does not affect the angle of motion of the drops.

A Time-Domain Multi-Tone Distortion Model for Effective Design of High Power Amplifiers

This paper proposes a new time-domain multi-tone distortion (TD-MTD) model suitable for accurately predicting the non-linear behavior of packaged high power radio frequency (RF) transistors over a range of discrete non-uniformly distributed frequencies. This proposed TD-MTD model uses a single expression rather than multiple distinct frequency specific behavioral models to describe the underlying behavior of the high power RF transistor at multiple fundamental frequencies. Furthermore its extraction is carried out using a time-domain representation of the travelling waves that can be acquired using a generic vector load-pull characterization system and without imposing additional requirements. The proposed model is extracted as an artificial neural network (ANN) and is implemented as a Netlist to serve in a harmonic balance simulator based power amplifier design process. The proposed model is validated in two phases. First, its ability to reproduce the large-signal behavior of a high power RF LDMOS transistor was demonstrated in simulation. Then, the TD-MTD model was used to validate the design of a high power two-way asymmetric Doherty power amplifier and the simulated output-power-dependent power efficiency, AM/AM, AM/PM and input return loss characteristics were compared to those obtained in measurement. The excellent agreement between the simulation and measurement results confirms the usefulness of the proposed model despite the simplicity of its extraction routine and measurement data.

Computation of Constant Gain and NF Circles for 60 GHz Ultra-low noise Amplifiers

Wireless communication is a constantly evolving and forging domain. The action of the RF input module is critical in the radio frequency signal communication link. This paper discusses the design of a RF high frequency transistor amplifier for unlicensed 60 GHz applications. The Transistor used for analysis is a FET amplifier, operated at 60GHz with 10 mA at 6.0 V. The simulation of the amplifier is made with the Open Source Scilab 6.0.1 console software. The MESFET is biased such that Sll = 0.9<30°, S12 = 0.21<-60°, S21= 2.51<-80°, and S22 = 0.21<-15o. It is found that the transistor is unconditionally stable and hence unilateral approximation can be employed. With these assumptions, the maximum value of source gain of the amplifier is found to be at 7.212 dB and the various constant source gain circles and noise figure circles are computed. The transistor has the following noise parameters: Fmin = 3 dB, Rn = 4 Ω, and Γopt = 0.485<155°. The amplifier is designed to have an input and output impedance of 50 ohms which is considered as the reference impedance.

Study of the suitable value of dead-time between control signals of transistors for a series-resonant inverter with phase-shift control in induction heating systems

Induction heating provides contactless, energy-efficient, accurate, and fast heating of electrically conductive materials. Due to its advantages, IH is increasingly used in different fields such as industry, medicine, and the household sector. High-frequency transistor converters for the induction heating system are often based on series-resonant inverters. This paper analyzes a phase-shift-controlled voltage-source series-resonant inverter for induction heating systems. Mathematical analysis was performed in order to obtain the expressions that describe the output current of the phase-shift-controlled series-resonant inverter in the steady-state mode. Based on the analysis and the obtained expressions of the output current, analytical expressions of the dead-time between the transistors’ control signals of the SRI are obtained. The analytical expressions for determining the value of the dead-time are obtained for two cases:
 1) zero value of the phase-shift;
 2) the phase shift is greater than zero.
 To verify the obtained analytical expressions of the output current, validation was performed in the MATLAB/Simulink environment by comparing the peak current values.
 The verification showed the high accuracy of the obtained expressions, the deviation between the calculated and simulated values of the peak current is less than 0.1 %. The made simplifications of the dead-time expressions also were verified by calculation, the deviation between the calculated values of the drain-to-source voltage at the end of the commutation and the expected value is no more than 3.6 %. The SRI prototype has been designed and implemented in order to validate the analytical and simulation results

Study of resonant transport in InAs-based quantum hot electron transistors

A study of transport in a quantum hot electron transistor made of an InAs/AlSb heterostructure is reported. It exhibited that the quantum hot electron transistors with a thick emitter efficiently prevented the parasitic base currents compared with transistors with a thin emitter. The static characteristics of the fabricated devices demonstrated an enhancement of the current gain of 9 and a collector breakdown voltage of 1.5 V with thick-emitter designed transistors. In optimized devices, the current is dominated by fast resonant tunneling that is promising for their future development of as high frequency transistors.

Black Phosphorus High-Frequency Transistors with Local Contact Bias.

Having a sizable band gap and high carrier mobility, black phosphorus (BP) is a promising two-dimensional material for high-frequency electronic and optoelectronic devices. Further, for metal-oxide-semiconductor field-effect transistors (MOSFETs) operating at high frequencies, they must have a top gate of submicron length instead of the commonly used global back gate. However, without the global back gate to electrostatically induce doping in BP, top-gated submicron BP MOSFETs have not reached their full potential mainly due to large contact resistances. Here, we report top-gated submicron BP MOSFETs with local contact bias electrodes to induce doping in the contact region. This resulted in reduced contact resistance and, in turn, orders of magnitude improvement in current capacity (>500 μA/μm) and peak transconductance (>40 μS/μm), if compared with top-gated BP transistors without any back-gating scheme. In turn, these improvements resulted in a forward current gain cutoff frequency of 37 GHz and a maximum frequency of oscillation of 22 GHz at room temperature, the highest reported for BP MOSFETs up to date.

Physics‐Based Simulation for Studying the Impact of Contact Resistance on DC and RF Characteristics of AlGaN/AlN/GaN HEMT

AbstractFormation of a two‐dimensional electron gas in AlGaN/AlN/GaN heterostructures plays a vital role in high power and high frequency device technology. Such kinds of heterostructures are used for the fabrication of high electron mobility transistors (HEMTs). Ohmic contacts to AlGaN/AlN/GaN‐based heterostructures with low contact resistance and smooth surface are crucial in the development of high power, high frequency transistors in the GaN system. In the present study, physics‐based simulation of impact of ohmic contact resistance on DC and RF characteristics of AlGaN/AlN/GaN HEMT on 6H‐SiC substrate has been addressed for the first time. Samples A, B, and C of contact resistance 0.25, 0.27, and 0.59 Ω * mm, respectively, were fabricated with different process variations. By using measured contact resistance values, physics‐based simulation of 100‐nm gate length GaN HEMT was done, and corresponding device behavior was studied using TCAD. It has also been shown that simulated results for AlGaN/AlN/GaN heterostructure are closely matching with reported measured data.

Noise Power Spectral Density Analysis for Silicon Carbide Substrate MESFET

This paper mainly concentrates on the transistors working functions, electrical characteristics and noise analysis at various operating voltages and temperatures. For this improvement authors are developed simulation methods for better results. The high frequency transistors are exposed with bunch of silicon carbide crystalline substances like 3C, 4H and 6H-SiC MESFETs. Because of the good researchers work, now a day’s all are compared the parameter in between of cubic and hexagonal crystalline structure of silicon carbide MESFETs. Silicon carbide material is having wide band gap because of this reason it’s useful for high energy and high frequency applications. The silicon carbide transistors are having large operating voltage in channel region because of this reason in channel region flows large current and also very less noise is produced. In wide band gap semiconductor transistors are produced very less noise compared to the various categories of substrates.

(Invited) 2D Materials for Electronic and Optoelectronic Applications: Growth and Device Integration

Atomically thin layers represent a novel class of materials with unique properties, like e.g. high electrical conductivity combined with high transparency in graphene or efficient light absorption and emission in transition metal dichalcogenides (TMDCs). Originally prepared by mechanical exfoliation for more basic scientific studies, recent developments in large area CVD growth techniques paved the path towards practical applications. In this contribution some of our recent efforts on 2D materials for electronic and optoelectronic applications will be presented. This includes CVD growth of graphene on both, metallic and semiconducting substrates, and selected applications, e.g., as transparent electrode or in high frequency transistors. In addition, large area fabrication approaches of TMDCs via MOCVD growth will be demonstrated and the potential of these ultrathin semiconductors for light emitting devices in the red spectral range will be discussed. As powerful tools for nanoscale material and device analysis confocal optics and electrical scanning force microscopy have been applied.

Key note speakers

Key note speakers

Probing charge trapping and joule heating in graphene field-effect transistors by transient pulsing

We use pulsed electrical studies to investigate the various processes that limit the current carrying capacity of graphene high frequency transistors. By investigating the transient response of these devices over a time scale that spans some twelve orders of magnitude, we identify the presence of four distinct processes that degrade the current: (1) charge injection into deep traps within the interior of the oxide; (2) Joule heating of the transistor substrate by hot carriers in the graphene channel; (3) equilibration of interfacial-state filling in response to voltage transients, and; (4) leakage of captured charge from the deep traps, once the pulsed voltage is removed. The time scale associated with these processes ranges from nanoseconds to hours, with process (1) being the fastest and process (4) the slowest. By pulsing the transistors on time intervals as short as a few nanoseconds, we therefore demonstrate how it is possible to obtain output characteristics from them that are essentially free from the influence of these different mechanisms. Under such conditions, the hot-carrier drift velocity is shown to saturate at the large values expected for intrinsic graphene. Beyond graphene, this approach of pulsed characterization of transistor performance should be broadly applicable to studies of other two-dimensional semiconductors, including transition-metal dichalcogenides, black phosphorous, silicene, and topological insulators.

Controlling the superluminal

controlling the superluminal

Enhanced magnetic response and metallicity in AB stacked bilayer graphene via Cr-doping

First-principles study for the electronic and magnetic properties of Cr atom doping in lower layer of AB bernal stacked bilayer graphene (BLG) is presented. This doping is analysed in three different configurations; (i) Hollow type (above the centre of C hexagon), (ii) Top-type (directly on the top of any C atom) and (iii) Bridge type (mid point of any C–C bond). It has been observed that the doping of Cr atom enlarges the interlayer spacing in BLG as compared to pure one. The Top-type (T-type) doping is found to be most stable energetically. The doping of Cr atom in all configurations generates the large spin polarization and induces the appreciable magnetic moment. Half metallicity has been obtained in Hollow type (H-type) doping with a suitable band gap of 0.28 eV in minority spin channel. The origin of magnetism has been identified via interactions of 3d-states of doped Cr atom with p-states of inequivalent C atoms present in the vicinity of doping site. The electron densities plots also confirm the metallic nature of Cr-doped BLG. Our results reveal that the resultant BLG has potential for futuristic applications such as high frequency transistors, spintronics, photodetectors and energy resources.

Nanoscale electrical characterization of graphene contacts to AlGaN/GaN heterostructures

AbstractIn this paper, we describe a highly reproducible method to transfer graphene (Gr) grown on copper by chemical vapour deposition to the surface of AlGaN/GaN heterostructures and we report a nanoscale electrical characterization of current transport at Gr contact to AlGaN. This latter investigation has been carried out using local current‐voltage measurements by conductive atomic force microscopy (CAFM), performed both on the Gr‐coated and bare AlGaN surface (reference). These analyses provide information on the lateral uniformity of the Schottky barrier height (SBH) between Gr and AlGaN. Gr contacts to AlGaN exhibit much more uniform and significantly lower SBH (∼0.4 eV) than common metals, such as gold, with SBH∼0.96 eV. These results can be useful for future applications in high frequency transistors based on AlGaN/GAN heterostructures and Gr. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A local bottom-gate structure with low parasitic capacitance for dielectrophoresis assembly and electrical characterization of suspended nanomaterials

A device including a pair of top electrodes and a local gate in the bottom of an SU-8 trench was fabricated on a glass substrate for dielectrophoresis assembly and electrical characterization of suspended nanomaterials. The three terminals were made of gold electrodes and electrically isolated from each other by an air gap. Compared to the widely used global back-gate silicon device, the parasitic capacitance between the three terminals was significantly reduced and an individual gate was assigned to each device. In addition, the spacing from the bottom-gate to either the source or drain was larger than twice the source-drain gap, which guaranteed that the electric field between the source and drain in the dielectrophoresis assembly was not distinguished by the bottom-gate. To prove the feasibility and versatility of the device, a suspended carbon nanotube and graphene film were assembled by dielectrophoresis and characterized successfully. Accordingly, the proposed device holds promise for the electrical characterization of suspended nanomaterials, especially in a high frequency resonator or transistor configuration.

A 300 mV sub-threshold region 2.4 GHz voltage-controlled oscillator and frequency divider with transformer technique for ultralow power RF applications

A new ultralow voltage 2.4 GHz voltage-controlled oscillator (VCO) and a divide-by-2 frequency divider circuits operating in a CMOS sub-threshold region using a transformer technique have been developed. In the sub-threshold region, the CMOS transistor high frequency performances are decreased to the point where oscillation and frequency division are challenging to achieve. The new proposed VCO uses the transformer feedback complementary VCO technique to improves VCO negative feedback gain. The circuits have been fabricated in a 65 nm standard CMOS process. The oscillation frequency is designed at 2.4 GHz under a 300 mV supply voltage. The total power consumption is 202 µW with noise performance of −96 dBc/Hz at 1 MHz offset. The new proposed frequency divider circuit consists of two stages master-slave D-type flip-flop (DFF). The DFF differential input is coupled to a transformer circuit instead of transistors to reduce the number of stacks. The minimum operating supply voltage is 300 mV with power consumption of 34 µW with a free-run frequency of 1.085 GHz.

Call for papers: Noise modeling of high-frequency semiconductor devices

Noise processes in solid-state active devices often determine their fundamental operational limits. This is especially true in situations where a device operates under tight sensitivity and accuracy constraints, as is the case in satellite communication systems, aerospace instrumentation, and deep-space radio astronomy. Today’s ultra-high frequency transistors that meet these demanding low-noise performance characteristics often leverage progressive device downscaling techniques in conjunction with improved semiconductor alloys. To enable the design of next-generation low-noise devices, however, accurate and flexible models that characterize the connection between the physics of microscopic noise processes and measurable macroscopic performance are called for. The objective of this Special Issue is to collect and disseminate recent results addressing the topic of modeling and simulation of the macroscopic noise performance of highfrequency transistors including but not limited to GaAs-based and GaN-based field-effect transistors, Si metal–oxide–semiconductor FETs and FinFETs, InP-based high-electron-mobility transistors, and GaAs and SiGe heterojunction bipolar transistors. It is worth pointing out that because of frequency up-conversion phenomenacaused by a device’snonlinearities,lowfrequencynoiseprocessesmaystrongly impact microwave and millimeter wave behavior as well. Contributions focusing on low-frequency noise modeling therefore will be considered as well. This issue will include both invited and contributed manuscripts. Manuscripts for this Special Issue should adhere to the requirements for regular papers of the IJNM as specified in the Author Guidelines at http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-1204/ homepage/ForAuthors.html. Potential contributors may contact the Guest Editors to determine the suitability of their contribution to the Special Issue. All manuscripts should be submitted via the IJNM’s manuscript website http://mc. manuscriptcentral.com/ijnm, with a statement that they are intended for this Special Issue.

New Double Current Controlled CFA (DCC–CFA) Based Voltage–Mode Oscillator with Independent Electronic Control of Oscillation Condition and Frequency

In this paper, a new electronically tunable quadrature oscillator (ETQO) based on two modified versions of current feedback amplifiers (CFAs), the so called double current controlled CFA (DCC-CFAs) is presented. The frequency of oscillation (FO) of the proposed voltage-mode (VM) ETQO is electronically adjustable by current gain or by varying the intrinsic resistance of the X terminal of the active element used. The condition of oscillation (CO) is adjustable by current gain independently with respect to frequency of oscillation. Simultaneous control of current gain and intrinsic resistance allows linear control of FO and provides extension of frequency tuning range. In the proposed circuit all the capacitors are grounded. The use of only grounded capacitors makes the proposed circuit ideal for integrated circuit implementation. The presented active element realized by using BiCMOS technology and the behavior of proposed circuit are discussed in details. The theoretical results are verified by SPICE simulations based on CMOS ON-Semi C5 0.5 μm and bipolar ultra high frequency transistor arrays Intersil HFA 3096 process parameters.