Monolithic HEMT-HBT integration by selective MBE

We have achieved successful monolithic integration of high electron mobility transistors and heterojunction bipolar transistors in the same microwave circuit. We have used selective molecular beam epitaxy and a novel merged processing technology to fabricate monolithic microwave integrated circuits that incorporate both 0.2 μm gate-length pseudomorphic InGaAs-GaAs HEMTs and 2 μm emitter-width GaAs-AlGaAs HBTs. The HEMT and HBT devices produced by selective MBE and fabricated using our merged HEMT-HBT process exhibited performance equivalent to devices fabricated using normal MBE and our baseline single-technology processes. The selective MBE process yielded 0.2 μm HEMT devices with g_m=600 mS/mm and f_T=70 GHz, while 2×10 μm² HBT devices achieved β>50 and f_T=21.4 GHz at J_c=2×10⁴ A/cm². The performance of both a 5-10 GHz HEMT LNA with active on-chip HBT regulation and a 20 GHz Darlington HBT amplifier are shown to be equivalent whether fabricated using normal or selective MBE     

Monolithic integration of InGaAsP/InP lasers and heterostructure bipolar transistors by selective area epitaxy

The authors describe the use of selective area epitaxy to prepare monolithically integrated lasers and heterostructure bipolar transistors based on InGaAsP/InP. Selective growth offers a versatile method of lateral integration of structurally dissimilar devices with the different device structures grown side by side in different growth cycles. Individual devices can be optimised separately without any performance compromise. Bipolar transistors grown on the semi-insulating current blocking layers of the buried heterostructure lasers show high gain, high breakdown voltage and excellent high current stability. Laser threshold is reached at a base current as low as 160 mu A and the light output is linear with current to 10 mW.<>     

Polarization-insensitive semiconductor optical amplifier arraygrown by selective MOVPE

Polarization-insensitive 1.3 μm wavelength semiconductor optical amplifier (SOA) arrays are developed for the first time, by using a new fabrication process with selective MOVPE. In a four-channel array, the SOAs have uniform device characteristics of more than 20 dB signal gain and less than 1 dB polarization sensitivity     

HCl-free selective epitaxial Si-Ge growth by LPCVD forhigh-frequency HBTs

Low-temperature HCl-free selective silicon germanium epitaxial growth using low-pressure chemical vapor deposition was developed. By utilizing the incubation period of the poly-SiGe growth on SiO₂ , sufficient selectivity was obtained without the use of HCl gas. The advantages of this HCl-free process are sufficient growth rate at low temperature (660°C) and capability of high-concentration boron doping without surface roughening. The thickness uniformity of the selectively grown layers throughout a wafer was good and the local loading effect did not appear. These results show the process can be used for fabricating heterojunction bipolar transistors (HBTs). The HBTs fabricated using the process have excellent yields and high-frequency characteristics, that is, 80-GHz cutoff frequency and 160-GHz maximum oscillation frequency. These characteristics and good uniformity of cutoff frequency throughout a wafer show that developed selective growth process can be applied to production of SiGe HBTs     

An investigation of low-frequency noise in complementary SiGe HBTs

We present a comprehensive investigation of low-frequency noise behavior in complementary (n-p-n + p-n-p) SiGe heterojunction bipolar transistors (HBTs). The low-frequency noise of p-n-p devices is higher than that of n-p-n devices. Noise data from different geometry devices show that n-p-n transistors have an increased size dependence when compared with p-n-p transistors. The 1/f noise of p-n-p SiGe HBTs was found to have an exponential dependence on the (intentionally introduced) interfacial oxide (IFO) thickness at the polysilicon-to-monosilicon interface. Temperature measurements as well as ionizing radiation were used to probe the physics of 1/f noise in n-p-n and p-n-p SiGe HBTs. A weak temperature dependence (nearly a 1/T dependence) of 1/f noise is found in both n-p-n and p-n-p devices with cooling. In most cases, the magnitude of 1/f noise is proportional to I/sub B//sup 2/. The only exception in our study is for noise in the post-radiation n-p-n transistor biased at a low base current, which exhibits a near-linear dependence on I/sub B/. In addition, in proton radiation experiments, the 1/f noise of p-n-p devices was found to have higher radiation tolerance than that of n-p-n devices. A two-step tunneling model and a carrier random-walk model are both used to explain the observed behavior. The first model suggests that 1/f noise may be caused by a trapping-detrapping process occurring at traps located inside IFO, while the second one indicates that noise may be originating from the emitting-recapturing process occurring in states located at the monosilicon-IFO interface.     

Monolithic Integration of InP HBTs and Uni-Traveling-Carrier Photodiodes Using Nonselective Regrowth

This paper describes the monolithic integration of InP HBTs and uni-traveling-carrier photodiodes (UTC-PDs) by nonselective regrowth. HBTs are fabricated from nonselectively regrown device layers and UTC-PD subcollector layers, which are grown first on a 3-in InP substrate. This makes it possible to optimize the layer design for the HBTs and UTC-PDs independently and minimize the interconnection between them. The fabricated HBTs have a collector thickness of 200 nm, and they show an f_t of 260 GHz and an f_max of 320 GHz at a collector current density of 2.5 mA/mum². The standard deviations of the f_t and f_max across the wafer are 1.7% and 4.4%, respectively. The length of the interconnection between the HBTs and UTC-PDs can be made as small as 10 mum without any degradation of the regrown-HBT performance. The UTC-PDs fabricated on the same wafer exhibit a 3-dB bandwidth of 100 GHz and an output voltage of 1.0 V. There is no drawback in the performance of either device, as compared with that of discrete devices. We also demonstrate 100-GHz optical-input divide-by-two optoelectronic integrated circuits (OEICs) consisting of InP HBTs and a UTC-PD using this technique. These results indicate that the nonselective regrowth is promising for application toward over 100-Gb/s OEICs.     

All selective MOVPE grown BH-LDs fabricated by the novel self-alignment process

1.3 /spl mu/m-strained MQW BH LDs with a current blocking structure have been developed by selective MOVPE and a newly developed self-alignment process; we call these devices ASM (all selective MOVPE grown)-BH-LDs. The fabrication process, which completely eliminates semiconductor etching, is very promising to realize high-performance LDs with excellent uniformity and reproducibility. The light output power was remarkably improved by a factor of two, compared with previous selective MOVPE-LDs.     

Integrated npn/pnp GaAs/AlGaAs HBTs grown by selective MBE

npn and pnp GaAs/AlGaAs heterojunction bipolar transistors have been successfully fabricated on the same GaAs substrate using selective molecular beam epitaxy and a new merged HBT processing technology. The DC and microwave characteristics of the transistors are equivalent to those of similar HBTs grown by conventional MBE on separate GaAs substrates.<>     

Monolithic LED arrays by selective liquid-phase epitaxy in GaP

Progress in the fabrication of monolithic matrix-addressed arrays of light-emitting diodes (LED's) in GaP using selective liquid-phase epitaxy is reviewed. The structures of two red arrays and one green array are discussed in detail. Photographs of the arrays are shown to demonstrate their capability as alphanumeric displays which may be easily interfaced with silicon integrated circuits. The use of selective liquid-phase epitaxy (LPE) to make flip-chip bonded displays is also discussed.     

InAIGaAs selective MOVPE growth with bandgap energy shift

We studied the bandgap energy shift by varying the SiO₂ mask width in selective MOVPE growth of InAIGaAs with almost no polycrystals on the masks. We found that the photoluminescence (PL) peak shifts toward the longer wavelength with wider mask width and narrower mesa width, where the In content is enhanced, and observed a maximum PL peak wavelength shift of 170 nm.     

高性能微惯性器件单片集成技术

讨论了高性能微惯性器件单片集成技术。首先对单片集成MEMS技术的优势及面临的困难进行了讨论,并对目前主流的单片集成MEMS技术特点、工艺流程进行了介绍,最后,给出高性能微惯性器件单片集成技术的未来发展趋势。     

Migration effect on semiconductor surface for narrow-stripe selective MOVPE

Anovelmethod for deriving the migration length (L_m) on a semiconductor surface is discussed. L_m is the most important parameter but it has not been precisely investigated for narrow-stripe selective-MOVPE. L_m can be deduced from the relationship between the (111) B-facet length and the (100)-facet length in the edge-growth region formed at the side of SiO₂ masks. The two lengths have a linear relationship, so L_m on (100) surface can be obtained from an extrapolation of this relationship. This method was used to evaluate L_m for many kinds of the growth conditions. The maximum L_m and the precursors’ incorporation life-time were also deduced using the proposed method.     

Monolithic integration for a camera control system

Outlines the integrated circuit designs used within the first- generation version of an electronic subsystem developed specifically for the Polaroid SX-70 automatic camera. In particular, interactions between selected packaging technologies, performance requirements, cost effectiveness, and circuit design are examined.     

Monolithic integration of pseudomorphic power and low-noise HEMTs

Monolithic integration of pseudomorphic power and low-noise high electron mobility transistors (HEMTs) on a GaAs substrate has been demonstrated using specially designed multiple epitaxial layers. MBE-grown layers with three heterojunctions were selectively recessed to provide optimum structures for low-noise and power operations. At 18 GHz, a record power-added efficiency of 59% with 8 dB gain and 0.4 W/mm power density was obtained for the power HEMT. The low-noise device from the same slice achieved a noise figure of 1 dB with 9 dB associated gain at the same frequency.<>     

Monolithic integration of SEEDs and VLSI GaAs circuits by epitaxy on electronics

Using the epitaxy-on-electronics (EoE) process, self-electrooptic effect devices (SEEDs) have been monolithically integrated with VLSI GaAs electronics. The EoE approach provides both depletion-mode and enhancement-mode MESFETs for large-scale, high-density optoelectronic circuits. The performance of SEEDs grown by molecular beam epitaxy at a reduced temperature compatible with the EoE process is shown to be robust, and modulators with contrast ratios of 2.3:1 at 7.5-V bias have been integrated on commercially processed VLSI GaAs circuits. The EoE-SEED process offers potential improvements over the FET-SEED process, facilitating the applications of SEEDs in free-space optical switching and computing.     

Monolithic integration of Si MOSFET's and GaAs MESFET's

Integration of Si MOSFET's and GaAs MESFET's on a monolithic GaAs/Si (MGS) substrate has been demonstrated. The GaAs MESFET's have transconductance of 150 mS/mm for a gate length of 1 µm, and the Si MOSFET's have transconductance of 19 mS/mm for a gate length of 5 µm and an oxide thickness of 800 Å. These characteristics are comparable to those for devices fabricated on separate GaAs and Si substrates.     

Monolithic integration of optical neurochip with variablesensitivity photodetector

A monolithic integration of an optical neurochip with variable interconnection capability is reported. The neurochip is a three-dimensional optoelectronic integrated circuit, in which a variable sensitivity photodetector is directly fabricated on a light emitting diode. The principle of operation and the fundamental characteristics of the monolithic neurochip are described in detail. The optical crosstalk was significantly reduced and the optical coupling efficiency between the light emitting diode and the variable sensitivity photodetector was improved as compared to the previous hybrid structure. The monolithic neurochip is suitable for a large scale integration because there is little optical crosstalk, high efficiency, and no need of optical alignment     

GeSi调制器与探测器单片光电集成

文章以ＧｅＳｉ材料为基础，从理论和实践两方面讨论将波导、调制器、探测器集成在一起的可能性，分析结果表明，三者之间的光集成在理论上是可行的，在工艺上也是可以实现的。     

Monolithic integration of InAs photodiode and GaAs MESFET

InAs pn diodes were grown in wells pre-etched in GaAs substrates. Despite the large lattice mismatch of 7.2% between GaAs and InAs, good photodiode characteristics were obtained with 77 K resistance area products of 70 Omega cm/sup 2/ and a peak detectivity of 1.25*10/sup 11/ cm square root (Hz)/W at 2.95 mu m wavelength. GaAs MESFETs were fabricated next to the embedded detectors demonstrating for the first time the feasibility of the monolithic integration of InAs photodiodes and GaAs electronic circuits.<>     

A transceiver PIC for bidirectional optical communication fabricated by bandgap energy controlled selective MOVPE

A transceiver PIC consisting of a DFB-LD, a receiver PD and a Y-shaped branch waveguides is realized by in-plane bandgap energy controlled selective MOVPE. Both active and passive core layers are formed in one step selective growth, and complicated fabrication procedure is no longer required. More than 1 mW fiber coupled power and 7 GHz receiver bandwidth are obtained. The modulation and detection operations at 500 Mb/s are successfully demonstrated.