Analysis of Compressively Strained GaInAsP–InP Quantum-Wire Electro-Absorption Modulators

Performance of compressively strained (CS) GaInAsP-InP quantum-wire (QWR) electro-absorption modulators (EAMs) is theoretically studied using an eight-band kldrp model. An empirical relationship is proposed for the quantum-confined Stark shift in QWR EAMs. The accuracy of this relationship is verified by comparing with numerical data. The effects of the variation of different device parameters on the absorption spectra are investigated. The absorption peaks are found to be stronger in narrower QWRs with strain-compensating barriers. Comparison of the extinction ratio with that of similar quantum-well EAMs show that, in spite of the lower in-plane filling factor, QWR EAMs exhibit a higher extinction ratio. Effect of fluctuation of wire width on the absorption spectrum of QWRs has been studied. The proposed QWR EAMs are suitable for photonic integrated circuits (PICs) fabricated by electron-beam lithography, reactive-ion etching, and two-step epitaxial growth. Due to the nature of the integration in such structures, the QWR EAMs are not required to be polarization-insensitive. On the contrary, the QWR EAMs are naturally tuned to the polarization of the output of the CS QWR lasers, fabricated on the same PIC, leading to an enhancement of the absorption strength. Moreover, the QWR EAMs, integrated with QWR lasers, offer low insertion loss.     

Super-flat (411)A interfaces and uniformly corrugated (775)B interfaces in GaAs/AlGaAs and InGaAs/InAlAs heterostructures grown by molecular beam epitaxy

Extremely flat interfaces, i.e. effectively atomically flat interfaces over a wafer-size area were realized in GaAs/AlGaAs quantum wells (QWs) grown on (411)A GaAs substrates by molecular beam epitaxy (MBE). These flat interfaces are called as “(411)A super-flat interfaces”. Besides in GaAs/AlGaAs QWs, the (411)A super-flat interfaces were formed in pseudomorphic InGaAs/AlGaAs QWs on GaAs substrates and in pseudomorphic and lattice-matched InGaAs/InAlAs QWs on InP substrates. GaAs/AlGaAs resonant tunneling diodes and InGaAs/InAlAs HEMT structures with the (411)A super-flat interfaces were confirmed to exhibit improved characteristics, indicating high potential of applications of the (411)A super-flat interfaces. High density, high uniformity and good optical quality were achieved in (775)B GaAs/(GaAs)_m(AlAs)_n quantum wires (QWRs) self-organized in a GaAs/(GaAs)_m(AlAs)_n QW grown on (775)B GaAs substrates by MBE. The QWRs were successfully applied to QWR lasers, which oscillated at room temperature for the first time as QWR lasers with a self-organized QWR structure in its active region. These results suggest that MBE growth on high index crystal plane such as (411)A or (775)B is very promising for developing novel semiconductor materials for future electron devices.     

Formation of InP-based quantum structures by selective MBE on patterned substrates having high-index facets

In view of applications to next-generation electronics based on quantum devices, this paper presents and discusses the results of a systematic study recently done by the authors' group on the growth conditions, characterization and device application of InP-based In_0.52Al_0.48As/In_0.53Ga_0.47As quantum wires and dots formed by selective M13E growth on mesa-patterned (001) InP substrates. First, selective MBE growth experiments of InAlAs/InGaAs wire and dot structures on patterned (001) InP substrates are discussed generally. Then, particular attention is paid to successful growth conditions and properties of (110) oriented InAlAs/InGaAs ridge quantum wires (QWRs), including the effect of misorientation of mesa stripes. Finally, device related issues such as successful surface passivation by a technique using a silicon interface control layer (Si ICL) and electronic transport characterization by QWR transistors are discussed. The QWR transistor exhibited excellent gate-controlled one-dimensional transport with the appearance of clear conductance oscillations near pinch-off, visible up to about 50K.     

Low-drive voltage intersectional waveguide optical switch usingGaInAs/InP MQW structure

A low-drive voltage intersectional waveguide optical switch using 1.6 μm GaInAs/InP MQW (multiple quantum well) structure, which was fabricated by only one-step epitaxial growth of MQW structure followed by a one-step pattern etching of the waveguide is demonstrated. Extinction ratio at the straight port of 9.9 dB and that at the reflection port of 4.4 dB were obtained at an applied voltage of -4 V     

InAs/InP量子点激光器制备工艺研究

报道了通过化学湿刻蚀制备窄脊条InAs/InP量子点激光器的方法。激光器脊条主要是由半导体材料InGaAs和InP构成,通过选择合适配比的H2SO4∶H2O2∶H2O和H3PO4∶HCl腐蚀溶液和InP的腐蚀方向,在室温下选择性地腐蚀了InGaAs和InP,获得了窄脊条宽为6μm的量子点激光器。此激光器能够在室温连续波模式下工作,激射波长在光纤通信重要窗口1.55μm,单面最大输出功率超过12mW。     

Quantum wire lasers

Recent progress in the development of the concept and technology of semiconductor quantum wire (QWR) lasers is reviewed. In these quasi-one-dimensional structures, optical gain is provided by charge carriers that are quantum mechanically confined in two dimensions within wire-like active regions. These devices are expected to exhibit improved laser performance, including extremely low threshold currents (in the μA range), higher modulation bandwidth, narrower spectral linewidth, and reduced temperature sensitivity. QWR lasers would thus be particularly useful in applications involving densely packed laser arrays and monolithic integration of lasers with low-power electronics, including computer optical interconnects, optical computing, and integrated optoelectronic circuits. Approaches for fabricating these novel structures are reviewed, and recent successful demonstrations of lasing in semiconductor QWRs are described. Prospects for further progress in this area are also discussed     

Selective lasing of InGaAs quantum-wire array on a V-grooved GaAssubstrate by distributed optical feedback

Distributed-feedback (DFB) lasers were fabricated by using strained InGaAs quantum-wire (QWR) arrays on V-grooved GaAs substrates as an active grating. After characterizing the luminescence from the QWRs and parasitic quantum wells (QWLs), a DFB laser cavity incorporating such a QWR array with its emission wavelength matched to the Bragg wavelength was designed and fabricated. The wavelength selectivity of the DFB cavity was found to strongly support the QWR emission, and DFB lasing from QWR gain up to 145 K has been achieved under pulsed current. The emission from the parasitic QWLs was suppressed by the DFB filtering and the loss induced by coupling to radiation modes. The DFB cavity was shown to be essential for obtaining lasing from QWRs on V-grooved substrates     

Threshold current reduction of GaInAs/GaInAsP/InP SCH quantum-welllasers with wire-like active region by using p-type substrates

The threshold current of GaInAs/GaInAsP/InP separate confinement heterostructure (SCH) quantum-well lasers with narrow (70-160-nm) wirelike active regions, which were fabricated by two-step LP-OMVPE growths and wet chemical etching, was much reduced (<1 kA/cm² ) by using p-type InP substrates. This result indicates the importance of eliminating the p-n junction from the regrowth interface to enhance injection of holes into the active region     

Switching operation in OMVPE grown GaInAs/InP MQW intersectionaloptical switch structures

An intersectional optical switch structure with an intersecting angle of 6° was fabricated on an organometallic vapor-phase epitaxy (OMVPE) grown GaInAs/InP multiple quantum-well (MQW) layered wafer. Switching operation using field-induced refractive index variation was successfully demonstrated at the reverse bias voltage of 8 V for the 1.6 μm wavelength region. Based on this switching, the field-induced refractive index variation in the QW was estimated as around 1%     

采用新的T型发射极技术的自对准InP/GaInAs单异质结双极晶体管的性能

研究了一种采用新的T型发射极技术的自对准InP/GaInAs单异质结双极晶体管.采用了U型发射极图形结构、选择性湿法腐蚀、LEU以及空气桥等技术,成功制作了U型发射极尺寸为2μm×12μm的器件.该器件的共射直流增益达到170,残余电压约为0.2V,膝点电压仅为0.5V,而击穿电压超过了2V.器件的截止频率达到85GHz,最大振荡频率为72GHz,这些特性使此类器件更适合于低压、低功耗及高频方面的应用.     

GaInAs metal/semiconductor/metal photodetectors with Fe:InP barrier layers grown by chemical beam epitaxy

A GaInAs metal/semiconductor/metal (MSM) photodetector with a dark current less than 1 mu A is described. An Fe-doped InP layer was introduced between the metal and the GaInAs absorbing layer to improve the Schottky barrier height. A breakdown voltage of 30 V was achieved. A DC quantum efficiency of 64% and an impulse response, 1/e fall time of 190 ps were measured for a 20 mu m*100 mu m device. The layer structure is very attractive for integration with high-performance GaInAs/InP FETs.<>     

InGaAs（InAIAs）／InP和InP／InAIAs湿法选择腐蚀研究

介绍了两种选择腐蚀液对InGaAs（InAlAs）／InP和InP／InAlAs异质结构材料选择腐蚀的实验结果，重点介绍在InAlAs上面生长InP的湿法选择腐蚀，用HCl：H3PO4：CH3COOH系列腐蚀液，InP／InAlAs选择比大于300。InP／InAlAs湿法选择腐蚀的结果可以很好应用到OEIC芯片制作中，并取得了较好的器件及电路结果。     

InGaAs(InAlAs)/InP和InP/InAlAs湿法选择腐蚀研究

介绍了两种选择腐蚀液对InGaAs(InAlAs)I/nP和InPI/nAlAs异质结构材料选择腐蚀的实验结果,重点介绍在InAlAs上面生长InP的湿法选择腐蚀,用HClH∶3PO4C∶H3COOH系列腐蚀液,InPI/nAlAs选择比大于300。InPI/nAlAs湿法选择腐蚀的结果可以很好应用到OEIC芯片制作中,并取得了较好的器件及电路结果。     

The effects of InP grown by He-plasma assisted epitaxy onquantum-well intermixing

He-plasma assisted InP (He*-InP) layers grown by gas source molecular beam epitaxy (GSMBE) have been employed to enhance quantum well (QW) intermixing induced by rapid thermal annealing in a 1.5 μm InGaAsP QW laser structure. Inserting a 40 nm He*-InP layer just above the active region enhances the blue-shift for anneal temperatures larger than 680°C, and a 42 nm additional blue-shift is obtained at 750°C for samples with the He*InP layer, compared to samples with normal InP replacing the He*-InP. This is accompanied by a reduction in the photoluminescence (PL) intensity for anneal temperatures greater than 600°C and is attributed to the migration of nonradiative defects from the He*-InP layer into the QWs. Insertion of a thin InGaAs layer between the He*-InP layer and the QW blocks the diffusion of these nonradiative defects into the QW. The results indicate that the He*-InP material could prove useful in QW intermixing to achieve integrated optoelectronic devices, in particular for high-frequency devices which require short carrier lifetimes     

一种实用的磷化铟MMIC背面工艺技术

采用湿法技术发展了磷化铟MMIC的背面通孔刻蚀工艺,PMMA用作粘片剂,InP衬底粘附于玻璃版上,溅射钽膜用作湿法刻蚀掩膜,HCl+H3PO4腐蚀液实现100μm的通孔腐蚀.已证实这种湿法通孔工艺宽容度大,精确可控.     

InGaAs/InP量子线的子带结构和光学增益

采用有效质量理论 6带模型 ,计算了 In0 .53Ga0 .4 7As/ In P量子线的光学性质 ,具体计算了In0 .53Ga0 .4 7As/ In P量子线的能带结构、态密度、载流子浓度、光学跃迁矩阵元和光学增益谱 ,并把量子线的光学增益谱和量子阱的光学增益谱作了比较。     

磷化铟的CH_4／H_2反应离子腐蚀研究

研究了用来制作ＩｎＰ微细结构的反应离子腐蚀（ＲＩＥ）技术，采用ＰＬＡＳＭＡＬａｂμＰＭｏｄｕｌａｒ反应离子腐蚀系统，在ＣＨ４／Ｈ２／Ａｒ环境中，研究了ＩｎＰ的腐蚀速率、表面形貌、剩余损伤层等随反应气体组分、压力等的变化。发现速率随ＣＨ４／Ｈ２比值增大而增大，随工作压强的增大而减小。测得的腐蚀速率很慢：从４ｎｍ／ｍｉｎ到１６ｎｍ／ｍｉｎ，腐蚀图形的方向性好，因而特别适合制作尺寸为微米级的ＩｎＰ微细结构，在ＣＨ４／Ｈ２＝０．１８５时，腐蚀后的表面光亮，腐蚀速率为１４．５ｎｍ／ｍｉｎ，剩余损伤层的厚度约为１５～３０ｎｍ。与参考文献报导不同处是：在腐蚀后较为粗糙的表面上，并不总是富Ｉｎ，有时是富Ｐ。由此提出了平衡腐蚀的概念。     

Flip-chip planar GaInAs/InP p-i-n photodiode array for paralleloptical transmission

A back-illuminated planar GaInAs/InP p-i-n photodiode array with a simple fabrication process was developed for application to parallel optical transmission. Four p-i-n photodiodes were integrated in the array. The average capacitance and dark current were as low as 0.12 pF and 8 pA, respectively, at -5 V. At a 1.55-μm wavelength, the quantum efficiency of each photodiode was over 80%. The cutoff frequency was 8-10 GHz with four photodiodes when the bias voltage was -3 V and the load resistance was 50 Ω. Crosstalk between channels was -12 dB at the cutoff frequency and -45 dB at 1 GHz     

Planar embedded InP/GaInAs p-i-n photodiode for very high-speed operation

Planar embedded InP/GaInAs p-i-n photodiodes have been fabricated by using preferential ion-beam etching for planarizing and embedding the p-i-n photodiode structure in a semi-insulating InP substrate. The stray capacitances caused by a bonding pad and an interconnection have been markedly reduced, which resulted in extremely low capacitance of less than 0.08 pF for a diameter of 20 μm of photosensitive area. It has been demonstrated by an optical heterodyne technique that the photodiode exhibits a maximum cutoff frequency of 14 GHz. This result was analyzed taking the depletion layer thickness into account and has been found to be dominated by the carrier transit time. The demonstrated low capacitance and high-speed response result indicates the suitability of the p-i-n photodiodes not only for a discrete p-i-n photodiode but also for optoelectronic integration.     

Quantum confined Stark effect in GaInAs/InP single quantum wellsgrown by low pressure MOVPE

Reports the first measurements of the quantum confined Stark effect in single GaInAs/InP quantum wells using photocurrent spectra from a single 80 Å well. Well resolved excitonic features are observed for values of electric field up to 3×10⁵ V/cm, whose field dependent shift and peak height are in excellent agreement with the predictions of an effective mass calculation, thus demonstrating that there are no intrinsic factors limiting the effect in the GaInAs/InP material system