Emitter Transistor Research Articles

Molecular beam epitaxial growth and physical properties of AlN/GaN superlattices with an average 50% Al composition

Abstract We report molecular beam epitaxial growth and electrical and ultraviolet light emitting properties of (AlN)m/(GaN)n superlattices (SLs), where m and n represent the numbers of monolayers. Clear satellite peaks observed in XRD 2θ-ω scans and TEM images evidence the formation of clear periodicity and atomically sharp interfaces. For (AlN)m/(GaN)n SLs with an average Al composition of 50%, we have obtained an electron density up to 4.48×1019 cm-3 and a resistivity of 0.002 Ω·cm, and a hole density of 1.83×1018 cm-3 with a resistivity of 3.722 Ω·cm, both at room temperature. Furthermore, the (AlN)m/(GaN)n SLs exhibit a blue shift for their photoluminescence peaks, from 403 nm to 318 nm as GaN reduced from n=11 to n=4 MLs, reaching the challenging UVB wavelength range. The results demonstrate that the (AlN)m/(GaN)n SLs have the potential to enhance the conductivity and avoid the usual random alloy scattering of the high-Al-composition ternary AlGaN, making them promising functional components in both UVB emitter and AlGaN channel high electron mobility transistor applications.

A 2.41 ppm/°C bandgap voltage reference with second‐order curvature compensation

SummaryA current‐mode (CM) bandgap voltage reference (BGR) with second‐order curvature compensation is presented in this paper. The proposed CM BGR offers a simple compensation structure that requires only six additional transistors compared with traditional BGR designs, making it an attractive solution for low temperature coefficient (TC) voltage references. Proportional to absolute temperature (PTAT) current digital‐to‐analog converters (DACs) are used to suppress the effect of process variation and device mismatch on TC. The compensation signal is generated using the voltage difference of two bipolar junction transistor (BJT) emitter–bases whose currents are the sum and difference of the PTAT current and the zero to absolute temperature (ZTAT) current, respectively. The proposed CM BGR is designed with 0.18‐μm BIPOLAR CMOS DMOS process. A TC is 2.41 ppm/°C over a wide temperature range of −40°C to 150°C. The linear sensitivity of the supply voltage from 1.2 to 2 V is 0.027%/V. With an active area of 0.0721 mm2, it consumes 68 μA at room temperature. The integrated output noise from 0.1 to 10 Hz is 21.9 μV.

A 2.25 ppm/°C High-Order Temperature-Segmented Compensation Bandgap Reference

This paper presents a bandgap reference (BGR) with high-order temperature-segmented compensation. The compensation signal is generated using the voltage difference between two bipolar junction transistor (BJT) emitter bases, each of which individually loads a proportional-to-absolute temperature (PTAT) current and a zero-to-absolute temperature (ZTAT) current. The proposed BGR achieves a low-temperature coefficient (TC) over a wide temperature range. Simulations using the 0.18 μm Bipolar-CMOS-DMOS process show a typical TC of 2.25 ppm/°C from −40 °C to 125 °C. With an active area of 0.07986 mm2, it consumes 36 μW power under an operating voltage of 1 V. The integrated output noise from 0.1 Hz to 10 Hz is 81.1 μV.

Numerical simulation of single-particle transients in low-noise amplifiers based on silicon-germanium heterojunction bipolar transistors and inverse-mode structures

In this work, TCAD simulation modeling is carried out for silicon-germanium heterojunction bipolar transistor (SiGe HBT), and an X-band low noise amplifier (LNA) circuit is built based on the SiGe HBT device model to carry out the hybrid simulation of single-particle transient (SET). The rule of SET pulse varying with LET value and incident angle of ions is studied, and the results show that with the increase of incident LET value, the amplitude of SET pulse at the LNA port increases, and the oscillation time is prolonged; with the increase of incident angle of ions, the amplitude of SET pulse at the LNA port first increases and then decreases, and the oscillation time decreases. With the development of the characterization process, the cutoff frequency (<i>f</i><sub>T</sub>) and the maximum oscillation frequency (<i>f</i><sub>MAX</sub>) of SiGe HBT device with IM structure, are measured considering the use of inverse-mode (IM) common emitter and common-base structures (Cascode) to reduce the sensitivity of the LNAs to single-particle effects. This work calibrates the devices of the TCAD platform as well as the devices of the ADS platform, establishes F-F LNAs as well as I-F LNAs on the ADS, respectively, and verifies the relevant RF performances of the LNA circuits by using the IM-structured SiGe HBTs as the core devices. The SET experiments are performed on the Sentaurus TCAD platform for the F-F LNA circuit and I-F LNA circuit for ions incident on two positions: common base transistor and common emitter transistor, respectively. It is concluded that the LNA with IM structure still shows good RF performance compared with the standard LNA at 130 nm. The transient current duration of the LNA circuit with IM Cascode structure is significantly reduced, and the peak value is reduced by 66% or more, which significantly reduces the sensitivity of the SiGe LNA circuit to SET.

Memory dependent triple-phase-lag thermo-elasticity in thermo-diffusive medium

The objective of the paper is to look at the propagation and reflection of plane waves in a thermo-diffusion isotropic medium. The reflection of plane waves in a thermo-diffusion medium was investigated in this study with reference to triple phase lag thermo-elasticity. The memory dependent derivative (MDD) is applied for this investigation. The fundamental equations are framed and solved for a particular plane. The four plane waves that are propagating across the medium are, shown namely: longitudinal displacement, P-wave, thermal diffusion T-wave, mass diffusion MD-wave and shear vertical SV-wave. These four plane wave velocities are listed for a specific medium, illustrating the impact of the diffusion coefficient and are graphically represented. Expressions for the reflection coefficient for the incidence plane wave are produced from research on the reflection of plane waves from the stress-free surface. It should be noted that these ratios are graphically represented and shown when diffusion and memory dependent derivative (MDD) factors are in play. The new model is relevant to many different fields, including semiconductors, earth- engineering, and electronics, among others, where thermo-diffusion elasticity is significant. Diffusion is a technique that can be applied to the production of integrated circuits, MOS transistors, doped polysilicon gates for the base and emitter in transistors, as well as for efficient oil extraction from oil reserves. Wave propagation in a thermos-diffusion elastic media provides crucial information about the presence of fresh and enhanced waves in a variety of technical and geophysical contexts. For experimental seismologists, developers of new materials, and researchers, this model might be useful in revising earthquake estimates.

Three‐Dimensional Porous Diboron Dinitride as a High‐Performance Anode Material for Sodium/Potassium‐Ion Batteries: A First Principles Study

Abstract2D boron nitride shows great promise in the photoelectric device, deep UV emitter and field effect transistor with good thermal stability, high mechanical robustness and chemical inertness; nonetheless, its inherently low electrical conductivity and small pore size have severely hindered the electrochemical kinetics and lead to a poor rate capability. Herein, we design a novel porous 3D−B2N2 structure by assembling the orthorhombic B2N2 monolayer into t‐C24 lattice and assesse its feasibility as the anode material of sodium(SIBs)/potassium(PIBs) ion batteries. The ab initio molecular dynamics (AIMD) simulation, Born‐Huang criteria, phonon spectrum and cohesive energy calculations confirms that the resulting 3D−B2N2 possesses excellent mechanical, thermal and dynamical stability. Different from the pristine h‐B2N2, an improved electrical conductivity is observed for 3D−B2N2 with a small band gap of 0.66 eV. Moreover, the low mass density, unique porous structure and strong adsorption energy make the 3D−B2N2 an outstanding electrode material for SIBs/PIBs with high storage capacities of 599.90 (479.92) mA h/g, low averaged open circuit voltages of 0.13 (0.27) V, low diffusion barriers of 0.04 (0.008) eV, and small volume expansions of 0.96 % (2.63 %). All the encouraging findings reveal that the 3D−B2N2 anode deserves further experimental investigation for SIBs/PIBs.

(Invited) Catalytic Growth of Width-Controlled Single Atomic Layer MoS2 Sub-10nm Nanoribbons

For the next generation materials for optoelectronics, quantum computing, communication and sensing, single atomic layer semiconducting nanoribbons offer additional degree of freedoms for engineering their properties. However, direct width-controlling synthesis of TMD nanoribbons, especially for the appealing width range below 30 nm, remains challenge. Therefore, developing facile methods for their direct and controllable synthesis is of central importance. We present a new growth method for single and double atomic layer of MoS2 nanoribbons with width down to sub-10 nm. Nanoribbons are grown via precipitation from the Ni-contained composite nanoparticles via vapor-liquid-solid mechanism in which the nanoparticle diameter also controls the width of nanoribbon. We also present preliminarily studies on width-dependent properties of the nanoribbons, which evidence their potential application in the quantum electronics, particularly as a single electron transistor and single photon emitter.

45‐2: Invited Paper: Towards High‐Performance Organic Transistors for Display and other Applications

Organic semiconductor devices have potential for displays as light emitter and organic backplane transistors. We present vertical transistor structures with very short channel length without micropatterning. These devices are well suited to drive organic light‐emitting diodes (OLED), allowing all‐organic flexible displays. We have achieved kA/cm2 current densities useful for bright OLED displays and record operating frequencies >40MHz /2/. Vertical organic light‐emitting transistors show efficient emission in different colors, combining OLED operation and switching and fully compatible with vacuum mass production. Vertical transistors have GHz potential using highly ordered layers grown quasi‐epitaxially.

Дослідження температурної нестабільності в активних НВЧ фільтрах та методи її зменшення

The article presents a study of methods for reducing temperature instability in active microwave filters. The analysis of the effect of temperature on the parameters of an active microwave filter is carried out. The results of experimental studies of the temperature characteristics of microwave filters are also presented. When designing digital systems, especially modern ones that operate with a clock frequency or that use a radio channel in the microwave and microwave range, there is usually a problem of increasing the reliability or reducing the overall size while maintaining high electrical parameters. Requirements for miniaturization of microwave equipment, the task is to create filter circuits that are suitable for integrated production. Unlike low-frequency active filters, when constructing microwave filters, it is necessary to take into account the inertial properties of transistors. Therefore, studies of various stripe active microwave filter circuits exploit reactive phenomena in the transistor. The possibility of their temperature and dynamic stabilization by changing the emitter current of a bipolar transistor is shown. Various circuit solutions for the implementation of this method are proposed. As experimental studies have shown, with increasing temperature, there is a decrease in the filter transfer coefficient at the quasi-resonant frequency. Experimental studies have shown that in order to stabilize the transfer coefficient of temperature rise, an increase in the emitter current is necessary, which can be achieved by a general increase in the supply voltage. Thus, for thermal stabilization of the frequency response of the microwave filter, it is necessary to regulate the current of the transistor emitter simultaneously with the temperature change. The magnitude of the emitter current adjustment when the temperature changes from –60 °C to +100 °C is 3—4 orders of magnitude for low-power silicon transistors.

Thermal behaviour evolution of an IGBT module after aging measured by thermoreflectance

In this paper, we propose to study the thermal mapping evolution of the Insulated gate bipolar transistor (IGBT) emitter metallization after aging by thermoreflectance. Thermoreflectance measurements were done in static regime before and after aging by DC power cycling. The aim of this study is to observe the change in thermal behaviour at the cell level due to power cycling aging. Preliminary results indicate that a pixel-by-pixel calibration which takes into account the topography and chemical changes of the metallization is essential to eliminate artefacts in thermal images and to allow to follow metallization thermal evolution with aging.

VO2-based radiative thermal transistor with a semi-transparent base

We study a radiative thermal transistor analogous to an electronic one made of a VO2 base placed between two silica semi-infinite plates playing the roles of the transistor collector and emitter. The fact that VO2 exhibits an insulator to metal transition is exploited to modulate and/or amplify heat fluxes between the emitter and the collector, by applying a thermal current on the VO2 base. We extend the work of precedent studies considering the case where the base can be semi-transparent so that heat can be exchanged directly between the collector and the emitter. Both near and far field cases are considered leading to 4 typical regimes resulting from the fact that the emitter-base and base-collector separation distances can be larger or smaller than the thermal wavelength for a VO2 layer opaque or semi-transparent. Thermal currents variations with the base temperatures are calculated and analyzed. It is found that the transistor can operate in an amplification mode as already stated in [1] or in a switching mode as seen in [2]. An optimum configuration for the base thickness and separation distance maximizing the thermal transistor modulation factor is found.

高密度模块化TDI CCD成像系统设计

In order to improve the high density assembly technology of remote sensing camera, a high density TDI CCD imaging system was designed with multichip module technology. First, TDI CCD focal plane with mechanical splicing technology was made to a copied unit. Then, the output energy of CCD output image signals was improved by a transistor emitter follower, they were transmitted to the analog front-end chips. Then they were converted into the 14 bits digital signals. After that they were integrated and processed through field programmable gate array (FPGA). In the end, through TLK2711 high-speed chip they were sent to data acquisition card on the computer. All the driving signals and processing signals of the imaging system were produced by the FPGA. The computer can control the imaging system and exchange the parameter through RS422 communication bus. The experimental results show that the area of driving layout cut down 2/3 than convention design. It realized the camera's high density assembly adopting the design of the mechanical and electrical integration of heat. And the total data speed can reach 3.6 Gbps in this imaging system, SNR can reach 52.6 dB.

Degradation of the parameters of transistor temperature sensors under the effect of ionizing radiation

The influence of the effective concentration of an impurity specifying the conduction type of the base region and the base thickness on the radiation resistance of transistor temperature sensors is investigated. The dependences of the forward voltage drop at the emitter transistor junction and current amplification factor on the magnitude of electron, neutron, and γ-quanta flows are revealed. It is found that degradation of the forward voltage drop under the effect of ionizing radiation begins at doses higher by almost two orders of magnitude than the current amplification factor depending on the transistor’s design features. The reproducibility of the temperature-sensitive parameter, which increases the yield percentage of suitable devices, increases after annealing of the electron-irradiated structures.

High Voltage Discharge Profile on Soil Breakdown Using Impulse Discharge

Grounding terminals are mandatory in electrical appliance design as they provide safety route during overvoltage faults. The soil (earth) been the universal ground is assumed to be at zero electric potential. However, due to properties like moisture, pH and available nutrients; the electric potential may fluctuate between positive and negative values that could be harmful for internally connected circuits on the grounding terminal. Fluctuations in soil properties may also lead to current crowding effect similar to those seen at the emitters of semiconductor transistors. In this work, soil samples are subjected to high impulse voltage discharge and the breakdown characteristics was profiled. The results from profiling discharge characteristics of soil in this work will contribute to the optimization of grounding protection system design in terms of electrode placement. This would also contribute to avoiding grounding electrode current crowding, ground potential rise fault and electromagnetic coupling faults.

Current Crowding Effect of Equilateral Polygon Emitter Transistors

This brief deals with current crowding in the equilateral polygon emitter transistor. Simple, analytical expressions are derived for the base current and the base resistance, which can be applied to specific emitter geometries, including the triangular, rectangular, hexagonal, and octagonal emitters. The solution for a device with circular symmetry is obtained when the side number of the polygon approaches infinite. The current crowding effects and the corresponding internal base resistances of different emitter geometries are compared and discussed.

Accuracy of analyses of microelectronics nanostructures in atom probe tomography

The routine use of atom probe tomography (APT) as a nano-analysis microscope in the semiconductor industry requires the precise evaluation of the metrological parameters of this instrument (spatial accuracy, spatial precision, composition accuracy or composition precision). The spatial accuracy of this microscope is evaluated in this paper in the analysis of planar structures such as high-k metal gate stacks. It is shown both experimentally and theoretically that the in-depth accuracy of reconstructed APT images is perturbed when analyzing this structure composed of an oxide layer of high electrical permittivity (higher-k dielectric constant) that separates the metal gate and the semiconductor channel of a field emitter transistor. Large differences in the evaporation field between these layers (resulting from large differences in material properties) are the main sources of image distortions. An analytic model is used to interpret inaccuracy in the depth reconstruction of these devices in APT.

21.4L: Late‐News Paper: Recent Developments of Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for OLED Displays

AbstractA new architecture light emitting transistor combining the drive transistor, storage capacitor and light emitter into a single device promises to greatly reduce AMOLED manufacturing costs by dramatically reducing the backplane circuit complexity. Here we demonstrate device operation at 60 Hz using only a switching transistor and show remarkable stability under bias stress, despite use of an organic channel.

Metal-insulator-semiconductor tunnel emitter transistor as a spintronic device: a concept

A possibility of exploiting the reversely biased metal–tunnel-thin insulator–n-type silicon structure as a bipolar spintronic transistor, is theoretically analyzed. Transistor action is due to an asymmetry between the tunnel leakage of holes and the electron injection current from the metal emitter. If ferromagnetic materials are used for the contact metallization, the gain value and other characteristics will be depending on the mutual orientation of the emitter and base magnetizations. Device operation, therefore, relies on both spin injection and the amplification properties. With different combinations of magnetization, a response of the transistor parameters and the current component evolution, to the feeding of base current, is simulated. The systems Fe3Si/SiO2(CaF2)/n-Si were chosen for exemplary illustrations.

Systems of Electronic Overcurrent Protection in Pulse Power Generator Operating on Plasma Load

Schematic peculiarities of pulsed power source and modulator-shaper for working on high instability plasma load are discussed. In its construction should be provided for several levels of overcurrent protection. First of all modules of electronic protection should be integrated into the control driver system of IGBT modules and must provide a quick disconnect power switches in excess of the allowable values of pulse current. The next level of overcurrent protection in pulse power generator is a protection against overcurrent in the load circuit. Operating threshold of current protection in this case must be set to the maximum value of current in the secondary circuit. In order to limit the emission of stray voltage on the power pulses in a moment of switching of power switches a restrictive RC snubbers parallel to the collectors and the emitters of transistors must be installed. It is also appropriate application of software-controlled configurating of electrical power at the outputof a pulsed power supply.

(Keynote) History and Future Directions in SiGe HBT BiCMOS Technology and Its Applications

The development of SiGe BiCMOS has mirrored silicon semiconductor development as the technology transitioned from Ge transistors, to silicon transistors, to ion-implanted base, to polysilicon emitter transistors, and finally to SiGe HBTs and SiGe BiCMOS. While the physics of the graded base SiGe HBT transistor was established early on in 1954 by Herb Kroemer it was not until the 1980s that SiGe HBTs were first realized. At the core of the SiGe Heterojunction Bipolar transistor development is the SiGe Epitaxy. In fact the SiGe HBT drove the development of the SiGe:B S/D processes now used for stressors in advanced CMOS since it was the first commercial technology with SiGe layers. SiGe HBT BiCMOS continues to find large volume production opportunities in applications that require mostly RF/Analog and less digital content (Big-A/little-D). Scaling has driven the speed performance ( f MAX ) towards terahertz levels to open up yet more applications. Many challenges still exist in the technology.