Heterojunction Bipolar Transistors Research Articles

Steady-State Characterization for Capture and Escape Lifetimes of 2-D Electron Gas in Light-Emitting Transistors

Quantum-well-based heterojunction bipolar light-emitting transistors (HBLETs or LETs) could work as candidate devices in optical communication and optoelectronic integrated circuits (OEICs) due to their multiport operation properties. The recombination process and capture-escape dynamics of carriers limit the device modulation bandwidth. The knowledge of capture and escape lifetimes is necessary to improve bandwidths. Here, we present a steady-state procedure rather than dynamic ones such as time-resolved photoluminescence (TRPL) or small-signal response to characterize the two lifetimes of LETs. On the experimental side, we perform dc measurements to investigate the electrical characteristics of the base–emitter (BE) junction of LETs. Theoretically, we formulate the charge-controlled model with continuity equations for electron concentrations in unbound and bound subbands of the quantum well (QW). The related capture and escape lifetimes are extracted with analytical expressions and the current gains of LETs. In the end, we verify our model by comparing the measured bandwidths to the unity gain bandwidths of this study.

DEPENDENCE OF TEMPERATURE DETERMINATION ACCURACY ON THE BANDWIDTH OF THE INTERFERENCE FILTER IN OPTICAL PYROMETRY SYSTEMS

Some general issues common to all reactors for gas-phase epitaxy of A3B5 metal-organic compounds include large temperature gradients in the reactor, leading to the formation of convection loops, high gas flow rates that can result in turbulence instead of the expected laminar flow, and the need for good uniformity and precision in temperature control of the semiconductor substrate surface. Since the deposition process for many complex semiconductor devices (such as infrared laser diodes or heterojunction bipolar transistors) is highly temperature-dependent, a system for precise temperature control of the process at the substrate surface directly in the deposition zone is necessary to obtain high-quality heterostructures with reproducible parameters.
 This article describes the features of the epitaxial growth process in MOCVD reactors, as well as highlights the tasks facing the temperature control system. The feasibility of using a radiation compensation system is explored in comparison to measurement methods using a thermocouple and classical pyrometry. Transformation of the input optical signal into a proportional output current in this system is performed by a sensitive photodetector, namely a silicon photodiode. The selection of the wavelength range of the radiation is determined by the optical parameters of the semiconductor substrates and compounds used in the system. The measurement spectrum is determined by the parameters of the interference filter in the system.
 The research was conducted to determine the effect of the interference filter width on the accuracy of determining the real temperature of a pyrometric control system with radiation compensation. The dependence of the interference filter characteristic width and shape on the correction value of the temperature of pyrometric systems after calibration is analyzed. Based on the results obtained, recommendations are made for selecting the optimal working wavelength and interference filter bandwidth of the optical system as a compromise between the determination error and the magnitude of the optical signal. The results can be used for the design of modern precision pyrometric systems.

Динамическая теплоэлектрическая модель гетеропереходного биполярного транзистора с учетом падения напряжения на эмиттерных дорожках металлизации

A dynamic 3D thermoelectric model has been developed to calculate the temperature field and emitter current density in the comb structure of a heterojunction bipolar transistor (HBT) with the length of the emitter metallization paths comparable to the size of the crystal, taking into account the inhomogeneous distribution of current density under the emitter paths caused by a voltage drop on the resistance of the current-carrying metallization. The model is based on an iterative solution in the COMSOL Multiphysics software environment of a non-stationary heat equation together with a system of equations for the distribution of electric potential along the emitter path and the current density under the path. It is shown that during the action of the heating power pulse in the HBT, the distribution of temperature and current density along the emitter tracks change character, respectively, from homogeneous and monotonically decreasing to non-monotonically changing. At the same time, the maximum temperature and current density reach stationary values with a rate significantly exceeding the rate of overheating increase with homogeneous heating of the structure, and the maxima of temperature and current density in the process of self-heating shift from the beginning to the center of the tracks. The proposed model can be used to evaluate the thermomechanical stresses in the structure of the HBT and the limiting electrical parameters in the pulsed modes of operation of the HBT.

A compact 9–23 GHzlow noise amplifier with bandwidth extension techniques in 0.18‐μmSiGe BiCMOS

AbstractIn this paper, a novel wideband low noise amplifier (LNA) operating in the 9–23 GHz frequency range is presented. The proposed LNA design utilizes a combination technique consisting of pole‐tuning technique, shunt resistive‐capacitor negative feedback, and gate‐capacitive peaking technique to achieve significant bandwidth extension while maintaining acceptable overall performance. For verification, a one‐stage triple‐stacked LNA using the combination technique is designed and implemented in a 0.18‐μm SiGe BiCMOS heterojunction bipolar transistor (HBT) process. The fabricated prototype demonstrates a peak gain of 13.8 dB at 19.5 GHz, minimum noise figure of 3.1 dB at 14 GHz, 3‐dB bandwidth of 14 GHz, and a fractional bandwidth of 87.5%, while consuming a dc power of 39.6 mW. Moreover, the chip occupies a small silicon area of 0.39 mm2including all testing pads with a core size of only 0.192 mm2.

Destructive Testing for Reliability Analysis at High-Power Microwave in GaAs/InGaP Hetero-Junction Bipolar Transistor

The destructive testing for reliability analysis at high-power microwave (HPM) in the GaAs/InGaP hetero-junction bipolar transistor (HBT) has been rarely investigated although it has a significant impact on their performance and reliability against HPM. This paper employs the experimental measurements to study the HPM damage process. We first establish the experiment platform for injecting the HPM to the GaAs/InGaP HBT which has the P1dB output power of +15.5 dBm to acquire the damage threshold. It is found that with the increasing of the input power, the output waveforms are gradually distorted. In particular, when the input power increases to 45 dBm, the S parameters of the GaAs/InGaP HBT chip show that it is totally destroyed. The experiment results show that the damage threshold of the HBT decreases with the increase of the pulse width, and the decrease rate of the damage threshold gradually slowed down with the increases of pulse width. The damage threshold can be reduced by increasing the pulse number from 1 to 10.

A 7–115-GHz Distributed Amplifier With 24-dBm Output Power Using Quadruple-Stacked HBT in InP

In this letter, we present the designs and development of a wideband, high output power quadruple-stacked heterojunction bipolar transistor (HBT) distributed amplifier (DA). In particular, the stacked HBT configuration can improve gain and output power while achieving a very wide bandwidth. To validate the proposed design concept, a quadruple-stacked HBT DA is designed in an indium phosphide (InP) process. The measurement results show an average gain of 16 dB from 7–115-GHz bandwidth with a maximum of 24-dBm saturated output power ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm{sat}})$</tex-math> </inline-formula> . To the best of the authors’ knowledge, this is the first time quadruple-stacked HBT is used in a DA to achieve the highest output power compared with other published work in the same frequency range.

Reliability studies on bipolar transistors under different particles radiation

The reliability of silicon bipolar junction transistors (Si BJTs) and silicon germanium heterojunction bipolar transistors (SiGe HBTs) were studied under 80 MeV nitrogen (N6+) ions and 60Co gamma radiation in a total dose from 1 to 100Mrad at 300 K. Different DC electrical parameters namely Gummel Characteristics (IB, IC–VBE), excess base current (ΔIB), current gain (hFE), and output characteristics (IC–VCE) were studied before as well as after being subjected to radiations. Both radiations caused substantial degradation in parameters such as an increase in IB, a decrease in the hFE, and a decrease in ICsat. The parametric degradation is more in Si BJT (99% degradation in hFE after ion irradiation) when compared to SiGe HBT (45% degradation in hFE). The SRIM/TRIM simulations were employed to analyze the energy loss phenomenon and ion range in device structures. Annealing studies were also conducted to study the recovery behavior of irradiated devices. The influence of linear energy transfer (LET) of radiations on damage mechanism is also discussed based on irradiation and annealing results. The results show that SiGe HBTs are more radiation hardened than Si BJTs.

AlGaN/GaN heterostructures for high power and high-speed applications

Abstract AlGaN/GaN heterostructures are one of the most promising semiconducting structures for fabricating high-speed and high-power electronic devices such as high electron mobility transistors and heterojunction bipolar transistors. Due to the lack of native substrates, these epitaxial structures are generally grown on foreign substrate materials such as sapphire, SiC and Si by using two-step growth techniques. In this paper, a few test structures along with TLM pads, FET structure, ohmic contacts and Schottky contacts have been fabricated on AlGaN/GaN heterostructure by photolithography, reactive ion etching, and e-beam metallization. Transmission line measurement has been used to calculate the sheet resistivity and contact resistance of ohmic pads. Current voltage measurement is used to test an FET structure of size 1 × 150 µm2 with a gate length of 4 µm and source to drain spacing of 5 µm.

(Invited) Integration of InP Heterojunction Bipolar Transistors on Silicon Substrates for 6G Networks

The power amplifier (PA) in an RF front-end module operating above 100 GHz required for 6G wireless networks is the most power-hungry device circuit component. In that respect, InP-based heterojunction bipolar transistors (HBT) clearly outperform other PA technologies, but being processed on small size wafers, they lack a cost-effective fabrication for mass production. This paper presents a comprehensive comparison of various integration approaches for InP-based HBTs. A key aspect in achieving high yield device fabrication is the use of large-diameter silicon wafers. This study discusses the advantages and disadvantages of different InP-based HBT integration concepts on Si, emphasizing important factors for upscaling InP technologies. Furthermore, this work introduces nano-ridge engineering (NRE), a novel monolithic III-V integration approach currently being explored at imec, which holds the potential for cost-effective and complementary metal oxide semiconductor (CMOS)-compatible production.

Burn-in effect in InGaP/GaAs HBT with intrinsically or extrinsically carbon doped base layer

InGaP/GaAs heterojunction bipolar transistors (HBTs) with intrinsically or extrinsically carbon doped base layers were grown by metal-organic chemical vapor deposition. Burn-in effect and the influence of thermal annealing at different temperatures on these devices were investigated. Results show that the intrinsically-carbon-doped HBTs demonstrate a higher current gain of 155 and a burn-in value of 24.0%, while the extrinsically-carbon-doped HBTs show a current gain of 92 and a burn-in value of 5.3%. Thermal annealing after exposing the base layer decreases the burn-in value from 24.0% to 5.7% and from 5.3% to 1.3% for intrinsically and extrinsically carbon doped HBTs, respectively, proved to be an effective method to eliminate the burn-in effect of HBT devices by hydrogen out diffusion. However, it also damages the base layer quality, leading to increased base recombination current and decreased current gain.

Performance investigation of low-power flexible n-ZnO/p-CuO/n-ZnO heterojunction bipolar transistor: Simulation study

Oxide semiconductor-based heterojunction bipolar transistors are widely applicable in flexible, printable, and cost-effective circuit applications. Among earth-abundant metal oxides, zinc oxide and copper oxide inherently show n-type and p-type characteristics, respectively, and their electronic properties can be easily modified during the fabrication process. Accordingly, a planar-type HBT can be achieved by low-temperature growth of the metal-oxide layers on a flexible substrate without the need for further sophisticated processes. In this paper, a double heterojunction bipolar transistor (DHBT) comprised of ZnO layers serving as the emitter and collector regions, along with the CuO layer functioning as the base area is presented. Simulation results demonstrate that the proposed all-metal oxide transistor based on p-CuO/n-ZnO heterojunction enjoys low power consumption owing to the low threshold voltage. High-frequency characterization and DC analysis of the proposed NPN configuration are carried out using the ATLAS/SILVACO package. Our findings reveal that at the base-emitter voltage of 0.55 V, the current gain factor of the device reaches 155, which is larger than those reported in the literature. Furthermore, an ideality factor at the base-emitter voltage of 0.7 V was obtained for the collector-base and emitter-base junctions equal to 1.5 and 1.2, respectively.

Optimized emitter-base interface cleaning for advanced Heterojunction Bipolar Transistors

Heterojunction Bipolar Transistors needed for high-frequency applications require precise dopant control. In-situ doped epitaxies used during device fabrication rely on surface preparation to obtain an optimized doping profile. Defects due to imperfect cleaning relates to high emitter resistance and low-frequency noise.Base epitaxy is followed by the fabrication of thin L-shaped oxide spacers and in-situ arsenic-doped emitter epitaxy by Low Pressure Chemical Vapor Deposition. A cleaning step between spacers formation and emitter epitaxy is mandatory to remove residual contamination. Hydrofluoric acid (HF) wet cleaning, in-situ remote plasma cleaning (SiconiTM) and thermal treatments have been tested. A minimum etching budget is sought for limiting spacer consumption while adequately cleaning the interface.Time Of Flight-Secondary Ion Mass Spectroscopy (TOF-SIMS) and High-Resolution Transmission Electron Microscopy (HR-TEM) are used to characterize the interface and measure levels of arsenic, oxygen, fluorine and carbon. Emitter resistance and base-emitter breakdown voltage measurements are used to show the impact on electrical figures of merit. Siconi targeting 10 Å of thermal oxide removal followed by a thermal treatment (800 °C, 60 s) in the deposition chamber results the best process among the tested ones.

High-Efficiency 200-GHz Neutralized Common-Base Power Amplifiers in 250-nm InP HBT

The analysis, design, and measurement of two Indium Phosphide (InP) heterojunction bipolar transistor (HBT) power amplifier (PA) designs are presented at G-band with record efficiency. A pseudo-differential common-base (CB) stage with neutralization capacitors and low-loss coupled-line balun (CLB) improve the gain and reduce matching loss. A single-stage design achieves 8.3 to 12.7-dBm output power and 7.7 to 17.3% power-added efficiency (PAE) over 180 to 220 GHz. The use of compact baluns allows the design to occupy only 0.011mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with power density of 1.69 W/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . A 3-stage, 4-way power-combined PA delivers 16.6 to 19.7-dBm output power and 6.5 to 13% PAE over 185 to 210 GHz.

A 2.2–4.2-GHz Wideband Analog Phase Shifter MMIC With Low RMS Phase/Amplitude Error

This letter presents a 2.2–4.2-GHz 360° continuous-tuned phase shifter (PS) using the Gallium arsenide (GaAs) heterojunction bipolar transistor (HBT) technology. A new method for broadband analog PS design based on a tunable low-pass network (LPN), a tunable high-pass network (HPN), and a magnetically coupled all-pass network (MCAPN) configuration is proposed to achieve uniform phase shifting and flat amplitude response at the same time for each phase-shifting state. The fabricated PS demonstrates a low average insertion loss (IL) of 4.9 dBC a low root-mean-square (rms) phase error of less than 5.5°, and a low rms amplitude error of less than 0.47 dB between 2.2 and 4.2 GHz. The proposed analog PS has the most flattened phase performance compared with previously reported pass PSs over a wide bandwidth.

A Review of Integrated Systems and Components for 6G Wireless Communication in the D-Band

The evolution of wireless communication points to increasing demands on throughput for data-intensive applications in modern society. Integrated millimeter-wave systems with electrical beam-steering capabilities are promising candidates for wireless technologies of the future and are currently the subject of widespread academic and commercial research. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band, ranging from 110–170 GHz, offers high aggregate bandwidths (BWs), low atmospheric absorption, and multi-GHz operation at amenable fractional BWs. It, therefore, has the potential to foster efficient, highly integrated wireless-communication systems with data rates approaching 100 Gb/s. This article reviews all aspects of hardware integration against the backdrop of an extensive literature review and outlines the challenges and possible solutions for practical 6G wireless systems in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band. To this end, this article covers a number of related topics in depth, which includes system definition, possible radio architectures and array configurations, the scope and potential of integrated circuit (IC) technologies, the design and characterization of key circuit blocks, advances in antenna and packaging technologies for high-frequency systems, and an overview of measurement techniques currently employed at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band frequencies. A system-level study based on radio-link simulations of different single-carrier quadrature amplitude modulation (QAM) schemes is presented, which quantifies that the impact physical nonidealities, such as signal-to-noise ratio, phase noise, intermodulation distortion, and amplitude and phase imbalances in quadrature signal paths, have on bit-error rates in broadband <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band communication systems. This is followed by a comparative assessment of different arrayed-system configurations that include traditional phased arrays, the use of polarization diversity for the transmission of different or identical data streams, and multiple input multiple output (MIMO) operation. The article also presents an overview of possible transceiver architectures for implementing beam-steering arrays and an outline of the associated tradeoffs. The beam-squinting effect seen in large arrays is also investigated in detail. On the implementation front, we present a comparison between different integrated-circuit technologies for high-frequency applications. These include CMOS and SiGe bipolar complementary metal oxide semiconductor (BiCMOS) heterojunction bipolar transistors (HBTs) in silicon technologies, and MOSFETs, HBTs, and HEMTs in III–V technologies, such as InP and GaAs. Implementation challenges are then addressed, and these include the design of high-frequency circuits in the latest IC technologies, current advances in antenna and packaging technologies, and emerging solutions for hybrid integration. The article also details the design and characterization of critical <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band transceiver circuit blocks, namely, power and low-noise amplifiers, mixers, phase shifters, passive components for quadrature-phase generation, and radiators exploring hybrid antennas, which we have developed over the course of the past five years. These results compliment the literature survey with comparisons with state-of-the-art designs and are applied to radio-link simulations to predict the performance of practicable wireless links.

High Linear and Temperature Insensitive GaAs Power Amplifier Operating at 3.3–3.6 GHz Using a Multi-Feedback Branch Bias Circuit

This letter describes a design of a 3.3–3.6-GHz GaAs heterojunction bipolar transistor (HBT) power amplifier (PA) with high linearity and temperature insensitivity for the fifth-generation (5G) of new radios (NRs). By involving a multi-feedback branches bias circuit, the voltage at the feedback node of the bias circuit can achieve dynamic self-tuning to stabilize the base voltage as the amplifier’s input power grows and stabilize the bias current as the temperature increases as well. A three-stage common source structure PA in the form of a monolithic microwave integrated circuit (MMIC) is designed using a multi-feedback branch bias circuit with a size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.5\times1.2$ </tex-math></inline-formula> mm. Measured with continuous wave (CW) signals, the output 1-dB compression point at 3.3–3.6 GHz is 34 dBm. The linearity of the PA is also evaluated using a 5G-NR 100-MHz 64-quadratic-amplitude modulated (QAM)-orthogonal frequency division multiplexing (OFDM) signal with a 7-dB peak-to-average-power ratio (PAPR). The proposed PA achieves an adjacent channel power ratio (ACPR) less than −49.5 dBc at an average power of 28 dBm with a power-added efficiency (PAE) of 20% without the use of digital pre-distortion (DPD). In the temperature range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 40\,\,^{\circ }\text{C}$ </tex-math></inline-formula> to 120 °C, the variance of bias current, small signal gain, PAE, output power at 1-dB compression point (OP1dB), and ACPR is relatively minor. This design is ideally suited for 5G communication systems due to its high linearity and temperature insensitivity.

Impact of Device Layout on Thermal Parameters and RF Performance of 90-nm SiGe HBTs

The present work investigates the impact of transistor layout on both the RF and thermal performance of 90-nm SiGe heterojunction bipolar transistors (HBTs). The resulting performance shows only slight degradation in small-signal RF figures-of-merit, while large-signal RF figures-of-merit relevant to power amplifiers (PAs) are improved. Thermal resistance and capacitance were extracted for five different SiGe HBT layouts with the same total emitter area. Additionally, a favorable trade-off exists between RF performance figures-of-merit and thermal parameters; namely, the thermal time constant can be reduced by up to 37% with optimal layout, with only slight degradation (up to 8%) in RF performance. These optimal device layout variations can help circuit designers mitigate thermal memory effects at the device level, thereby improving the overall large-signal linearity of PAs.

Effects of Different Factors on Single Event Effects Introduced by Heavy Ions in SiGe Heterojunction Bipolar Transistor: A TCAD Simulation

In this paper, the effects of different factors, including the heavy ions striking location, incident angle, linear energy transfer (LET) value, projected range, ambient temperature and bias state, on the single event transient introduced by heavy ions irradiation in the SiGe heterojunction bipolar transistor (HBT) were investigated by the TCAD simulation. The results show that the current transient peak value, collected charge and carrier type of each terminal are changed by the striking location, incident angle and bias state. The current transient peak value and collected charge increase with the LET value, while they decrease with the ambient temperature. When heavy ions vertically irradiate the collector and substrate, the current transient peak value and collected charge increase with the projected range; therefore, the species of heavy ions should be considered in studying the single event effects of the SiGe HBT induced by heavy ions irradiation. The microphysical mechanism of these factors influencing the single event effects of the SiGe HBT is discussed in this work.

On the Coupling Imbalance of the UWB BLC in the 5G Low Noise Amplifier Design

In this article, the design and the development of ultra-wideband UWB branch-line couplers BLCs with a novel method to control the coupling imbalance are proposed. The proposed UWB BLC is suitable for the 5G low-noise amplifier (LNA) design. UWB 4-branch BLC is designed using design curves developed using even and odd mode analyses to cover the 5G (3.3-5 GHz) frequency bands. The vertical branches of the UWB BLC are replaced by modified ones, and their effect on the coupling imbalance is investigated. The proposed BLC occupies an area of 33.9 × 15.7 mm2 Both conventional and modified BLC are fabricated, and their measured S-parameters are compared with analytical and simulated models. Based on the balanced amplifier topology, a 5G UWB low-noise amplifier is designed. The proposed BLCs and the MGF3022AM InGaP-HBT (Heterojunction Bipolar Transistor) are used to produce acceptable UWB performance. The balanced amplifier return loss, noise figure, and gain are investigated as BLCs coupling imbalance varies. The ultra-wideband LNA exhibits an acceptable small-signal gain, noise figure, input return loss, and output return loss across the 5G different frequency bands.

Repetitive High-Power Microwave Pulses Induced Failure on a GaAs HBT LNA

This study aims at studying the damage effect of gallium arsenide (GaAs) heterojunction bipolar transistor (HBT) low noise amplifier (LNA) with repetitive high-power microwave (HPM) pulses. The theoretical function for the thermal accumulation effect is derived, which depends on the pulsewidth, the pulse repetition frequency (PRF), and the input power. A simulation model is established to investigate the thermal accumulation effect of repetitive HPM pulses on the HBT. The electric field, current density, and temperature distributions in the HBT with repetitive HPM pulses are discussed first. The influence of the repetitive HPM pulse parameters on the thermal accumulation effect is studied by theoretical analyses and simulations. Results show that the thermal recovery time increases with the pulsewidth or the input power increases. In addition, it is concluded that the frequency does not affect the thermal recovery time. The simulation results agree with the theoretical results. Finally, the damage effect of repetitive HPM pulses is experimentally verified.