Zn-doped InGaAs Base Heterojunction Bipolar Transistors Grown by Low Pressure Metal Organic Chemical Vapor Deposition

High performance InP/InGaAs heterojunction bipolar transistors(HBTs) have been widely used in high-speed electronic devices and optoelectronic integrated circuits. InP-based HBTs were fabricated by low pressure metal organic chemical vapor deposition(MOCVD) and wet chemical etching. The sub-collector and collector were grown at 655 ℃ and other layers at 550 ℃. To suppress the Zn out-diffusion in HBT, base layer was grown with a 16-minute growth interruption. Fabricated HBTs with emitter size of 2.5×20 μm2 showed current gain of 70～90, breakdown voltage(BVCE0)＞2 V, cut-off frequency(fT) of 60 GHz and the maximum relaxation frequency(fMAX) of 70 GHz.     

Low-power high-speed operation of submicron InP-InGaAs SHBTs at 1 mA

Scaling of submicron InP-InGaAs HBTs is investigated for low-power high-speed applications in mixed signal circuits. Device performance for transistors fabricated with a 0.5-/spl mu/m emitter width and varying emitter lengths are studied. The 0.5 /spl mu/m/spl times/2 /spl mu/m devices yielded excellent low-current RF performance, with an f/sub T/=173 GHz and an f/sub MAX/=187 GHz at 1 mA, the highest values reported for InP-based devices to date.     

Analysis of heterojunction bipolar transistor/resonant tunnelingdiode logic for low-power and high-speed digital applications

A high-speed digital logic family based on heterojunction bipolar transistors (HBTs) and resonant tunneling diodes (RTDs) is proposed. The negative differential resistance of RTDs is used to significantly decrease the static power dissipation. SPICE simulations indicate that propagation delay time below 150 ps at 0.09-mW static power per gate should be obtainable     

The influence of emitter material on silicon nitride passivation-induced degradation in InP-based HBTs

The influence of emitter material on silicon-nitride (SiN) passivation-induced degradation in InP-based heterojunction bipolar transistors (HBTs) has been studied. It has been found that, compared to InP, InAlAs has a much higher resistance to NH/sub 3/-related plasma-induced damage. InP-based HBTs using InAlAs as the emitter can effectively suppress the degradation of device performance caused by dielectric passivation giving least deterioration on the device characteristics compared to the previously reported results concerning the passivation quality using different passivation schemes. Short-term high temperature and high current electrical stress tests indicates that the SiN-passivated devices using InAlAs as the emitter may have better stability than those with InP emitter. Our results suggest that engineering of emitter layer structures could be an alternative approach to suppress passivation-induced degradation in InP-based HBTs.     

Thermal properties and thermal instabilities of InP-basedheterojunction bipolar transistors

We investigate the physical parameters which are critical to the understanding of the thermal phenomena in InP-based heterojunction bipolar transistors. These parameters include thermal resistance, thermal-electric feedback coefficient, current gain, and base-collector leakage current. We examine the thermal instability behavior in multi-finger HBTs, and observe for the first time the collapse of current gain in InP-based HBTs. Based on both measurement and modeling results, we establish the reasons why the collapse is rarely observed in InP HBT's, in a sharp contrast to AlGaAs/GaAs HBT's. We compare the similarities and differences on how InP-based HBT, GaAs-based HBT, and Si-based bipolar transistors react once the thermal instability condition is met. Finally, we describe the issues involved in the design of InP HBTs     

A new RTD-FET logic family

We describe a new family of clocked logic gates based on the resonant-tunneling diode (RTD). Pairs of RTDs form storage latches, and these are connected by networks consisting of field-effect transistors (FETs), saturated resistors, and RTDs. The design, operation, and expected performance of both a shift register and a matched filter using this logic are discussed. Simulations show that the RTD circuits can achieve higher performance in terms of speed and power in many signal processing applications. Compared to circuits using III-V FETs alone, the RTD circuits are expected to run nearly twice as fast at the same power or at the same speed with reduced power. Compared to circuits using Lincoln Laboratory's fully depleted silicon-on-insulator CMOS, implementation using state-of-the-art RTDs should operate five times faster when both technologies follow the CMOS design rules     

RTD/CMOS nanoelectronic circuits: thin-film InP-based resonanttunneling diodes integrated with CMOS circuits

The combination of resonant tunneling diodes (RTDs) and complementary metal-oxide-semiconductor (CMOS) silicon circuitry can offer substantial improvement in speed, power dissipation, and circuit complexity over CMOS-only circuits. We demonstrate the first integrated resonant tunneling CMOS circuit, a clocked 1-bit comparator with a device count of six, compared with 21 in a comparable all-CMOS design. A hybrid integration process is developed for InP-based RTDs which are transferred and bonded to CMOS chips. The prototype comparator shows sensitivity in excess of 10⁶ VIA, and achieves error-free performance in functionality testing. An optimized integration process, under development, can yield high-speed, low power circuits by lowering the high parasitic capacitance associated with the prototype circuit     

Large-signal characteristics of InP-based heterojunction bipolartransistors and optoelectronic cascode transimpedance amplifiers

A large-signal model for InP/InGaAs-based single HBTs incorporating soft-breakdown effects to the LIBRA Gummel-Poon (GP) model is developed and its validity is established from DC to microwave frequencies and over a wide range of input excitation levels. The large-signal characteristics of a cascode InP-based transimpedance optoelectronic preamplifier employing such devices are studied. Gain compression for the preamplifier was found to take place at an input power level of -20 dBm. Input power excitation varying from -65 to -5 dBm results in a degradation of the amplifier transimpedance gain of the order of 3 dBn. Experimental and theoretical characteristics are presented for the InP-based HBTs and transimpedance amplifier. Self-biasing effects are suggested as possible origin of the transimpedance variations with input power     

InP/InGaAs heterojunction bipolar transistors with different g-bridge structures

Several μ-bridge structures for InP-based heterojunction bipolar transistors (HBTs) are reported. The radio frequency measurement results of these InP HBTs are compared with each other. The comparison shows that μ-bridge structures reduce the parasites and double μ-bridge structures have a better effect. Due to the utilization of the double μ-bridges, both the cutoff frequency f_T and also the maximum oscillation frequency f_(max) of the 2×12.5 μm~2 InP/InGaAs HBT reach nearly 160 GHz. The results also show that the μ-bridge has a better effect in increasing the high frequency performance of a narrow emitter InP HBT.     

A comparison of low-frequency noise characteristics and noise sources in NPN and PNP InP-based heterojunction bipolar transistors

Low-frequency noise characteristics of NPN and PNP InP-based heterojunction bipolar transistors (HBTs) were investigated. NPN HBTs showed a lower base noise current level (3.85 /spl times/ 10/sup -17/ A/sup 2//Hz) than PNP HBTs (3.10 /spl times/ 10/sup -16/ A/sup 2//Hz), but higher collector noise current level (7.16 /spl times/ 10/sup -16/ A/sup 2//Hz) than PNP HBTs (1.48 /spl times/ 10/sup -16/ A/sup 2//Hz) at 10 Hz under I/sub C/=1 mA, V/sub C/=1 V. The NPN devices showed a weak dependence I/sub C//sup 0.77/ of the collector noise current, and a dependence I/sub B//sup 1.18/ of the base noise current, while the PNP devices showed dependences I/sub C//sup 1.92/ and I/sub B//sup 1.54/, respectively. The dominant noise sources and relative intrinsic noise strength were found in both NPN and PNP InP-based HBTs by comparing the noise spectral density with and without the emitter feedback resistor. Equivalent circuit models were employed and intrinsic noise sources were extracted. The high base noise current of PNP HBTs could be attributed to the exposed emitter periphery and higher electron surface recombination velocity in P-type InP materials, while the relatively high collector noise current of NPN HBTs may be due to the noise source originating from generation-recombination process in the bulk material between the emitter and the collector.     

InP Bipolar ICs: Scaling Roadmaps, Frequency Limits, Manufacturable Technologies

Indium phosphide heterojunction bipolar transistors (HBTs) find applications in very wide-band digital and mixed-signal integrated circuits (ICs). Devices fabricated in high-yield process flows at 500 nm feature size obtain 450 GHz cutoff frequencies and 5 V breakdown and enable high yield fabrication of integrated circuits having more than 3000 transistors. Laboratory devices at 250 nm feature size obtain 755 GHz . We describe device and circuit bandwidth limits associated with HBTs, develop scaling roadmaps for HBTs having lithographic minimum feature sizes between 512 and 64 nm, and identify key technological challenges in realizing 480-GHz digital ICs and 1000-GHz amplifiers. Key features of manufacturable self-aligned dielectric sidewall processes are described in detail.     

Simulation study of compact quantising circuits usingmultiple-resonant tunnelling transistors

The authors have applied a simple modelling approach for multiple resonant tunnelling transistors (mRTTs) which includes four resonant tunnelling diodes (RTDs) within the transistor structure. Unique features of this model, corresponding to device features compatible for integrated circuits, allow far tuning and matching the devices for optimum circuit performance. Two circuits are presented for analogue to quaternary conversion with analysis of their transfer characteristics; this analysis is consistent with the simulation results and implies that circuits of physical devices may be successfully implemented     

Integrated circuit technology options for RFICs-present status andfuture directions

This paper will summarize the technology tradeoffs that are involved in the implementation of radio frequency integrated circuits for wireless communications. Radio transceiver circuits have a very broad range of requirements-including noise figure, linearity, gain, phase noise, and power dissipation. The advantages and disadvantages of each of the competing technologies-Si CMOS and bipolar junction transistors (BJTs), Si/SiGe HBTs and GaAs MESFETs, PHEMTS and HBTs will be examined in light of these requirements     

Making GaAs integrated circuits

Digital gallium arsenide (GaAs) integrated circuits offer prospects for high-performance electronics, particularly for increased speed and radiation hardness. Prototype GaAs devices fabricated in technologies ranging from ion-implanted metal semiconductor field-effect transistors (MESFETs) and junction field-effect transistors (JFETs) to epitaxial heterostructures, such as high-electron-mobility transistors (HEMTs) and heterojunction bipolar transistors (HBTs), have demonstrated these advantages. While these GaAs technologies share many common fabrication features, the unique characteristics of each and GaAs materials present significant manufacturing challenges. It is argues that to produce real integrated circuits (ICs) for system applications, the disciplines and rigors of a production environment as well as the innovations of research and development are required     

Performance comparison of state-of-the-art heterojunction bipolar devices (HBT) based on AlGaAs/GaAs, Si/SiGe and InGaAs/InP

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation.     

Recent progress in optoelectric integrated circuits (OEIC's)

Recent developments in both GaAs- and InP-based opto-electronic circuits (OEIC's) which incorporate both optoelectronic and electronic devices on the same semiconductor substrates will be discussed. Several key technologies required for optoelectronic integration and the present status of the technology are explained by reviewing some of OEIC transmitters and receivers that have been realized up to now. Possibilities of application of OEIC's and further technological challenges to enhance the advantages of OEIC's are discussed.     

Optoelectronic materials and devices

The development of epitaxial growth techniques, such as molecular beam epitaxy and metal-organic vapour phase epitaxy, allows us to control the growth of individual semiconductor layers on an atomic scale. These achievements provide a strong basis for fabricating new forms of active device with ‘tailor made’ characteristics. Novel electronic devices have been proposed and demonstrated in various fields. These include HBTs, HEMTs and RTDs. As well as these devices there has been enormous development in photonic and optoelectronic devices.     

RTD多值逻辑(MVL)电路

RTD具有双稳和自锁特性,用RTD构成电路可节省大量器件,这一优点在构建多值逻辑电路(MVL RTD)时显得尤为突出。在引用"遏止"概念的基础上介绍了几种典型的MVL RTD电路,包括多幅输入脉冲信号具有选幅功能的文字逻辑门、能提供三个不同电平输出的三态反相器、将一输入斜坡电压信号变成脉冲输出信号的折线量化器等电路;用"遏止"概念分析了异或门电路的工作原理。     

SiC电力电子器件研究现状及新进展

由于硅材料本身的限制,传统硅电力电子器件性能已经接近其极限,碳化硅(SiC)器件的高功率、高效率、耐高温、抗辐照等优势逐渐突显,成为电力电子器件一个新的发展方向.综述了SiC材料、SiC电力电子器件、SiC模块及关键工艺的研究现状,重点从材料、器件结构、制备工艺等方面阐述了SiC二极管、金属氧化物半导体场效应晶体管(MOSFET)、结晶型场效应晶体管(JFET)、双极结型晶体管(BJT)、绝缘栅双极晶体管(IGBT)及模块的研究进展.概述了SiC材料、SiC电力电子器件及模块的商品化情况,最后对SiC材料及器件的发展趋势进行了展望.     

Pseudomorphic AlInP/InP heterojunction bipolar transistors

Novel InP-based heterojunction bipolar transistors (HBTs) using an AlInP pseudomorphic emitter, together with an InP base and collector, have been fabricated. By using InP as both base and collector, the advantage of high electron velocity and high breakdown field of InP collectors are obtained without the problem associated with the energy barrier between the more standard InGaAs/InP base and collector heterojunction. Epitaxial layers were grown by gas-source molecular beam epitaxy (GSMBE). The 200 Å pseudomorphic emitter had an aluminium fraction of 15%, sufficiently suppressing hole injection from the base. The DC gain for 40×40 μm² devices reached 18. The breakdown voltage BV_CEO of 10 V is an improvement over devices with InGaAs base and collector layers