High-speed InP/InGaAs heterojunction bipolar transistors

Very-high-performance common-emitter InP/InGaAs single heterojunction bipolar transistors (HBTs) grown by metalorganic molecular beam epitaxy (MOMBE) are reported. They exhibit a maximum oscillation frequency (f_T) of 180 GHz at a current density of 1×10⁵ A/cm². this corresponds to an (R_BC_BC)_eff=f _T/(8πf²_max) delay time of 0.12 ps, which is the smallest value every reported for common-emitter InP/InGaAs HBTs. The devices have 11 μm² total emitter area and exhibit current gain values up to 100 at zero base-collector bias voltage. The breakdown voltage of these devices is high with measured BV_CEO and BV_CEO of 8 and 17 V, respectively     

Ultra-high-speed InP/InGaAs heterojunction bipolar transistors

We report on the microwave performance of InP/In_0.53Ga _0.47As heterojunction bipolar transistors (HBT's) utilizing a carbon-doped base grown by chemical beam epitaxy (CBE). The f_T and f_max of the HBT having two 1.5×10 μm² emitter fingers were 175 GHz and 70 GHz, respectively, at I_C=40 mA and V_CE=1.5 V. To our knowledge, the f _T of this device is the highest of any type of bipolar transistors yet reported. These results indicate the great potential of carbon-doped base InP/InGaAs HBT's for high-speed applications     

Be diffusion in InGaAs/InP heterojunction bipolar transistors

Classic signatures of Be diffusion were observed in InAlAs/InGaAs HBT's after elevated temperature bias stress, i.e., a positive shift in the Gummel plot, higher collector ideality, and higher offset voltage. An activation energy of 1.57 eV was calculated. Lifetimes of 3.3×106 h and 37000 h were extrapolated for low and high power operation, respectively. In contrast, an InP/InGaAs HBT with a C doped base showed no signatures of C diffusion. The results show that Be diffusion is manageable at lower power. They also support the idea that C is more stable than Be in this material system     

Magnetotransport characterization of surface-treated InP/InGaAs heterojunction bipolar transistors

The results of surface modification induced effects on InP/InGaAs single heterojunction bipolar transistors, as revealed by magnetotransport experiments, are described here. The surface treatments included both sulphur-based surface passivation and ion bombardment-induced surface damage. The former is known to improve device characteristics and the latter to degrade device operation. In this work the aim was to assess these techniques for tailoring device performance for surface sensing applications. Device characteristics were found to be sensitive to surface preparation prior to measurements. Measurements revealed that surface treatments that improve device performance also reduce sensitivity to external magnetic fields while treatments that degrade performance make devices more sensitive to externally applied magnetic fields.     

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.     

10Gbit/s InGaAs/InP雪崩光电二极管

基于InGaAs/InP吸收区、渐变区、电荷区和倍增区分离雪崩光电二极管(SAGCMAPD)器件结构,利用数值计算方法,模拟了各层参数对器件频率响应特性的影响.模拟结果表明,吸收层、倍增层厚度及电荷层面电荷密度可影响器件的-3 dB带宽;随增益的增加,器件带宽会逐渐降低;电荷层面电荷密度对器件击穿电压有明显影响.结合此模拟结果,制作出了高速InGaAs/InP雪崩光电二极管,并对器件进行了封装测试.测试结果表明,该结果与模拟结果相吻合.器件击穿电压为30 V;在倍增因子为1时,器件响应度大于0.8 A/W;在倍增因子为9时,器件暗电流小于10 nA,-3 dB带宽大于10 GHz,其性能满足10 Gbit/s光纤通信应用要求.     

Predicted performance of high-speed integrated-injection logicusing InGaAs/InP heterojunction bipolar transistors

By the use of analytical expressions and SPICE simulation, the switching performance of integrated injection logic (I²L) using heterojunction bipolar transistors (HBTs) has been investigated. A proposed inverter configuration using InP/InGaAs HBTs which avoids saturation in the p-n-p injector has predicted propagation delays of 16 ps at only 3-mW power dissipation. Transient response analysis illustrates the importance of reducing parasitic resistances in the structure. Ring oscillator simulations indicate that switching speeds approaching those of emitter-coupled logic but with advantages in high density and low power are possible     

Millimetre-wave InP/InGaAs heterojunction bipolar transistors witha subpicosecond extrinsic delay time

We report the microwave characteristics of InP/InGaAs heterojunction bipolar transistors (HBTs) using a carbon-doped base grown by chemical beam epitaxy (CBE). An extrinsic delay time of 0.856 ps was achieved by nonequilibrium transport in a very thin base layer and extremely small emitter parasitic resistance through the use of silicon δ-doping in the emitter ohmic contact layer. To our knowledge, this is the shortest extrinsic delay time of any bipolar transistors reported. This result indicates the great potential of InP/InGaAs HBTs for applications requiring a very large bandwidth     

Low-base-resistance InP/InGaAs heterojunction bipolar transistors with a compositionally graded-base structure

To reduce base resistance of an InP/InGaAs heterojunction bipolar transistor grown by gas-source molecular beam epitaxy, the doping characteristics of carbon-doped InGaAs and the dependence of doping concentration on current gain were investigated. Using a thicker graded base was found to increase current gain significantly, resulting in increased doping level in the InGaAs: C-base layer. In particular, an 80-nm-thick graded base produces a base sheet resistance of 285 Ω/sq and maintains a practically useful current gain of 23 and a high cut-off frequency of 139 GHz.     

Monolithically integrated long wavelength photoreceiver OEIC based on InP/InGaAs HBT technology

The epitaxial structure and growth, circuit design, fabrication process and characterization are described for the photoreceiver opto-electronic integrated circuit (OEIC) based on the InP/lnGaAs HBT/PIN photodetector integration scheme. A 1.55 μm wavelength monolithically integrated photoreceiver OEIC is demonstrated with self-aligned InP/lnGaAs heterojunction bipolar transistor (HBT) process. The InP/lnGaAs HBT with a 2 μm × 8 μm emitter showed a DC gain of 40, a DC gain cutoff frequency of 45 GHz and a maximum frequency of oscillation of 54 GHz. The integrated InGaAs photodetector exhibited a responsivity of 0.45 AAV at λ = 1.55 μm, a dark current less than 10 nA at a bias of -5 V and a -3 dB bandwidth of 10.6 GHz. Clear and opening eye diagrams were obtained for an NRZ 223-l pseudorandom code at both 2.5 and 3.0 Gbit/s. The sensitivity for a bit error ratio of 10-9 at 2.5 Gbit/s is less than -15.2 dBm.     

High-speed InAlAs/InGaAs heterojunction bipolar transistors

InAlAs/InGaAs heterojunction bipolar transistors fabricated from wafers grown by molecular beam epitaxy are discussed. A cutoff frequency of 32 GHz for a collector current of 20 mA is achieved in the emitter area of devices 6×10 μm². The use of heavily doped and nondoped InGaAs layers as the emitter cap and collector, respectively, results in a reduction of the emitter and collector charging times; this, in turn, leads to improved microwave performance     

Subpicosecond InP/InGaAs heterostructure bipolar transistors

Bipolar transistors with subpicosecond extrinsic delay are discussed. These InP/InGaAs heterostructure transistors show a unity-current-gain cutoff frequency f_$T=165 GHz and maximum oscillation frequency f_MAX=100 GHz at room temperature. The authors model shows that an f_$T beyond 386 GHz is obtainable by further vertical scaling. Ring oscillators implemented with nonthreshold logic (NTL) and transistors having f_MAX=71 GHz show a propagation delay of 14.7 ps and 5.4 mW average power consumption per stage     

16 Gbit/s multiplexer IC using double mesa Si/SiGe heterojunction bipolar transistors

A double mesa Si/SiGe heterojunction bipolar transistor (HBT) was developed for application in integrated circuits. The HBT is characterised by an emitter base heterojunction and consequently by a high base doping concentration. By using these transistors an integrated digital circuit, a multiplexer, was implemented. The measured bit rate of this first Si/SiGe HBT circuit was 16 Gbit/s.<>     

Selfaligned InGaAs/InP heterostructure bipolar transistors

InGaAs/InP heterostructure bipolar transistors have been realised using a new selfaligned process. Transistor wafers were grown by chemical beam epitaxy. Ideality factors close to unity were measured for emitter-base and collector-base diodes. The resulting devices exhibit nearly constant gain over four orders of magnitude of collector current densities, from j=1.5*10/sup -4/ A/cm/sup 2/ to 1.5 A/cm/sup 2/.<>     

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     

Digital integrated circuit using GaInAs/InP heterojunction bipolar transistors

A divider circuit using GaInAs/InP heterojunction bipolar transistors is reported for the first time. This is the first monolithic digital integrated circuit using these devices. The divider has been clocked at 5 GHz, which is the fastest toggle rate for a bipolar circuit on InP.<>     

Metamorphic InP/InGaAs heterojunction bipolar transistors on GaAssubstrate: DC and microwave performances

High-performance InP/In_0.53Ga_0.47As metamorphic heterojunction bipolar transistors (MHBTs) on GaAs substrate have been fabricated using In_xGa_1-xP strain relief buffer layer grown by solid-source molecular beam epitaxy (SSMBE). The MHBTs exhibited a dc current gain over 100, a unity current gain cutoff frequency (f_T) of 48 GHz and a maximum oscillation frequency (f_MAX) of 42 GHz with low junction leakage current and high breakdown voltages. It has also been shown that the MHBTs have achieved a minimum noise figure of 2 dB at 2 GHz (devices with 5×5 μm ² emitter) and a maximum output power of 18 dBm at 2.5 GHz (devices with 5×20 μm² emitter), which are comparable to the values reported on the lattice-matched HBTs (LHBTs). The dc and microwave characteristics show the great potential of the InP/InGaAs MHBTs on GaAs substrate for high-frequency and high-speed applications     

Degradation of InGaAs/InP single heterojunction bipolar transistors under high energy electron irradiation

The d.c. characteristics of InGaAs/InP single heterojunction bipolar transistors (SHBTs) were studied for the first time under high energy (1 MeV) electron radiation of cumulative dose up to 5.4×10¹⁵ electrons/cm². No degradation was observed for electron doses below 10¹⁵/cm². For electron doses greater than 10¹⁵/cm² the following degradation effects were observed: (1) decrease in collector current; (2) decrease in current gain up to 50%; (3) an increase in collector saturation voltage by 0.2–0.8 V depending on base current; and (4) increase in output conductance. The degradation of collector current and current gain are thought to be due to increased recombination caused by radiation-induced defects in the base–emitter junction. The increase in collector saturation voltage is attributed to an increase in emitter contact resistance after irradiation. The increase in the avalanche multiplication in the reverse biased base–collector junction caused by radiation induced defects is believed to be responsible for increased output conductance after irradiation.     

10Gbit/s台面型InGaAs/InP pin高速光电探测器

利用数值计算方法分析了高速光电探测器的耗尽区宽度与响应度及响应速度的关系.分析结果表明,耗尽区宽度选择应在响应度和响应速度之间折中,在响应度满足使用要求的情况下,尽量提高响应速度.利用该分析结果设计了台面型InGaAs/InP pin高速光电探测器材料结构.通过优化腐蚀工艺与钝化工艺,解决了器件腐蚀形貌和钝化问题.结合其他微细加工工艺完成了器件的制备,器件光敏区直径50 μm.测试结果显示,在反向偏压为5V时,暗电流小于1 nA,电容约为0.21 pF.此外,在1 310 nm激光辐照下,器件的响应度约为0.95 A/W,-3 dB带宽超过10 GHz,其性能满足10 Gbit/s光纤通信应用要求.