非对称In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As量子阱的零场自旋分裂能与高场g因子（英文）

研究了非对称In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As量子阱中二维电子气的磁输运性质,所测量的样品的径向磁阻R_(xx)的Shubinikov-de Haas振荡没有呈现出拍频的特征。通过测量样品的反弱局域效应提取了其零场自旋分裂能并通过对自旋分裂的R_(xx)双峰间距随倾斜角度θ的依赖关系的拟合提取了高场下的有效g因子。样品的Dingle plot图呈现非线性的特征,这可以归因于来自样品衬底附近的掺杂Be原子的长程势散射效应     

有效跨导为1052 mS/mm的高性能InP基In0.52Al0.48As/In0.53Ga0.47As HEMTs

我们成功研制了栅长为0.15 μm、栅宽为2?50 μm、源漏间距为2 μm 的InP 基In_0.52Al_0.48As/In_0.53Ga_0.47As高电子迁移率器件。室温下,当器件V_DS为1.7 V,V_GS为0.1 V时,其有效跨导达到了1052 mS/mm。传输线方法(TLM)测试显示器件的接触电阻为0.032 Ω.mm,器件欧姆接触电阻率为1.03?10_-7Ω.cm_-2. 正是良好的欧姆接触及其短的源漏间距减小了源电阻,进而使得有效跨导比较大。器件还有比较好的射频特性：当V_DS＝1.5 V, V_GS ＝0.1 V 时,f_T和f_max分别为151 GHz,303 GHz。文章报道的HEMT器件非常适合毫米波段集成电路的研制。     

（英）数字递变异变赝衬底上2.6 μm In0.83Ga0.17As/InP光电探测器的性能改进

本文研究了In_0.83Al_0.17As/In_0.52Al_0.48As数字递变异变缓冲层结构(DGMB)的总周期数对2.6 μm延伸波长In_0.83Ga_0.17As光电二极管性能的影响。实验表明,在保持总缓冲层厚度不变的情况下,通过将在InP衬底上生长的In_0.83Al_0.17As/In_0.52Al_0.48As DGMB结构的总周期数从19增加到38,其上所生长的In_0.83Ga_0.17As/In_0.83Al_0.17As光电二极管材料层的晶体质量得到了显著改善。对于在总周期数为38的DGMB上外延的In_0.83Ga_0.17As光电二极管,观察到其应变弛豫度增加到99.8％,表面粗糙度降低,光致发光强度和光响应度均增强,同时暗电流水平被显著抑制。这些结果表明,随着总周期数目的增加,DGMB可以更有效地抑制穿透位错的传递并降低残余缺陷密度。     

InyAl1-yAs线性渐变缓冲层对InP基HEMT材料性能的影响

采用气体源分子束外延（GSMBE）技术,研究了InP衬底上In_yAl_1-yAs线性渐变缓冲层对In_0.66Ga_0.34As/In_yAl_1-yAs高迁移率晶体管（HEMT）材料特性影响。研究了不同厚度和不同铟含量的In_yAl_1-yAs线性渐变缓冲层对材料的表面质量、电子迁移率和二维电子气浓度的影响。结果表明,在300 K（77 K）时,电子迁移率和电子浓度分别为8 570 cm²/（Vs）^-1（23 200 cm²/（Vs）-1）3.255E12 cm^-2（2.732E12 cm^-2）。当In_yAl_1-yAs线性渐变缓冲层厚度为50 nm时,材料的表面形貌得到了很好的改善,均方根粗糙度（RMS）为0.154 nm。本研究可以为HEMT器件性能的提高提供强有力的支持。     

The preparation of Gal-x Inx As by organometallic pyrolysis for homojunction LED’S

Ga_1-x}In_x}As epitaxial layers have been deposited on GaAs substrates using the technique of organometallic pyrolysis (metalorganic chemical vapour deposition). The deposition was performed in a laminar flow, resistively heated, reactor. Both n and p-type (10¹⁷}-10¹⁸} carriers/cm³}) epitaxial layers, several microns thick,were prepared, with values of x in the range 0 ≤x ≤0.3. Epitaxial layer characterisation was carried out using conventional electrical, optical and x-ray techniques. Restricted emitting area (50–75 μm diameter) zinc-diffused LED’s were prepared in ungraded epitaxial layers with emission spectral peaks in the range 0.9 —1.15 ym. External quantum efficiencies of these devices decreased rapidly with increasing x, from∼0.4% for GaAs LED’s to∼0.02% for Gao._0.75}In_0.25}As LED’s.     

截止波长2.2 µm的平面型延伸波长InGaAs探测器

采用闭管扩散的方法成功研制了截止波长2.2 μm的平面型延伸波长InGaAs探测器芯片。在分子束外延法（MBE）生长的In_0.75Al_0.25As/ In_0.75Ga_0.25As/ In_0.75Al_0.25As外延材料上,采用砷化锌作为扩散掺杂源、SiN_x作为扩散掩膜层,实现了扩散成结。分析了扩散结深和载流子侧向收集宽度、I-V特性、光谱响应特性和探测率,结果表明：150 K温度下,器件暗电流密度0.69 nA/cm²@-10 mV,响应截止波长和峰值波长分别为2.12 μm和1.97 μm,峰值响应率为1.29 A/W,峰值量子效率达82%,峰值探测率为1.01×10¹² cmHz^1/2/W。这些结果对后续进一步优化平面型延伸波长InGaAs焦平面探测器有重要的指导意义。     

用InGaAs材料制作的2.6 μm光电探测器

2.6 μm In_0.82Ga_0.18As/InP P-N heterojunction photodetectors are introduced.A compositionlly graded layer is effective to accommodate the 20% lattice mismatch between the InP substrate and the In_0.82Ga_0.18As active layer of the device.The quantum efficiency is 70%～75% over the wavelength of 2.1 μm～2.6μm,with dark current of 3.5 μA at -2 V reverse bias and the room temperature.     

22 nm In0.75Ga0.25As channel-based HEMTs on InP/GaAs substrates for future THz applications

In this work, the performance of L_g=22 nm In_0.75Ga_0.25As channel-based high electron mobility transistor (HEMT) on InP substrate is compared with metamorphic high electron mobility transistor (MHEMT) on GaAs substrate. The devices features heavily doped In_0.6Ga_0.4As source/drain (S/D) regions, Si double δ-doping planar sheets on either side of the In_0.75Ga_0.25As channel layer to enhance the transconductance, and buried Pt metal gate technology for reducing short channel effects. The TCAD simulation results show that the InP HEMT performance is superior to GaAs MHEMT in terms of f_T, f_max and transconductance (g_{m_max}). The 22 nm InP HEMT shows an f_T of 733 GHz and an f_max of 1340 GHz where as in GaAs MHEMT it is 644 GHz and 924 GHz, respectively. InGaAs channel-based HEMTs on InP/GaAs substrates are suitable for future sub-millimeter and millimeter wave applications.     

分子束外延高铟组分InGaAs薄膜研究

研究了分子束外延生长条件对高铟组分InGaAs材料性能的影响,分析了生长温度、V/III比和As分子束形态对In_0.74Ga_0.26As材料光致发光和X射线衍射峰强度、本底载流子浓度和迁移率的影响。测试结果表明：适中的生长温度和V/III比可以提高材料晶格质量,减少非辐射复合,降低本底杂质浓度。As分子束为As₂时In_0.74Ga_0.26As材料质量优于As₄分子束。当生长温度为570 ℃,As分子束形态为As₂,V/III比为18时,可以获得较高的光致发光和X射线衍射峰强度,室温和77 K下的本底载流子浓度分别达到6.3×10¹⁴ cm^-3和4.0×10¹⁴ cm^-3,迁移率分别达到13 400 cm²/Vs和45 160 cm²/Vs。     

In0.53Ga0.47As/In0.52Al0.48As量子阱二维电子气中的零场自旋分裂与塞曼分裂

利用变角度磁输运方法研究了高迁移率、高浓度、宽度为20 nm、单边δ掺杂的In0.53Ga0.47As/In0.52Al0.48As量子阱,根据量子阱平面与磁场不同夹角时SdH振荡的拍频节点移动,提取了其自旋分裂能Δ0和有效g因子|g*|,发现Δ0随浓度增加而增大,|g*|随浓度增加而减小.进一步的分析和计算表明,|g*|减小是由量子阱能带结构的非抛物性作用引起的.     

Thermal stability of Al0.48In0.52As/Ga0.47In0.53As/InP heterostructure and its improvement by phosphidization

A drastic decrease in the sheet carrier concentration of modulation-doped Al_0.48In_0.52As/Ga_0.47In_0.53As/InP heterostructures has been observed after O₂ plasma treatment followed by thermal treatment up to 350°C. The decrease in sheet carrier concentration, which is speculated to be caused by both plasma damage and impurities penetrating from the surface of the epilayer, can be suppressed substantially by using PH₃ plasma treatment prior to the O₂ plasma and thermal treatments.     

120-nm gate-length In0.7Ga0.3As/In0.52Al0.48As InP-based HEMT

120 nm gate-length In_(0.7)Ga_(0.3)As/In_(0.52)Al_(0.48) As InP-based high electron mobility transitions(HEMTs) are fabricated by a new T-shaped gate electron beam lithograph(EBL) technology,which is achieved by the use of a PMMA/PMGI/ZEP520/PMGI four-layer photoresistor stack.These devices also demonstrate excellent DC and RF characteristics:the transconductance,maximum saturation drain-to-source current,threshold voltage,maximum current gain frequency,and maximum power-gain cutoff frequency of InGaAs/I...     

Persistent photoconductivity and electron mobility in In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As/InP quantum-well structures

The influence of the width of the quantum well L and doping on the band structure, scattering, and electron mobility in nanoheterostructures with an isomorphic In_0.52Al_0.48As/In_0.53Ga_0.47As/In_0.52Al_0.48As quantum well grown on an InP substrate are investigated. The quantum and transport mobilities of electrons in the dimensionally quantized subbands are determined using Shubnikov-de Haas effect measurements. These mobilities are also calculated for the case of ionized-impurity scattering taking into account intersub-band electron transitions. It is shown that ionized-impurity scattering is the dominant mechanism of electron scattering. At temperatures T < 170 K, persistent photoconductivity is observed, which is explained by the spatial separation of photoexcited charge carriers.     

Sheet electron concentration at the heterointerface in Al0.48In0.52As/Ga0.47In0.53As modulation-doped structures

Sheet electron concentration at the heterointerface in Al0.48In0.52As/Ga0.47In0.53As modulation-doped structures has been calculated as a function of the spacer layer thickness, the doping concentration in Al0.48In0.52As and the lattice temperature. The calculated results were compared with those for Al0.3Ga0.7As/GaAs structures and also with the experimental data. It is shown that, compared with AlGaAs/GaAs about 1.5 times higher sheet electron concentration can be obtained in AlInAs/GaInAs at the same doping level, which is in good agreement with the experimental results.     

Transferred-electron oscillations in In0.53Ga0.47As

Transferred-electron oscillations were observed and investigated in planar devices of In0.53Ga0.47As. The peak-to-peak magnitude of oscillations with respect to the device current at threshold field was as high as 70%, indicating the peak-to-valley velocity ratio of 3.3:1 for this material. The domain velocity was estimated from the oscillation frequency (2 GHz) and the corresponding device length (40 ?m) to be 8×106 cms?1. The results presented in the letter show a promising prospect for TED applications of this ternary alloy.     

DC and microwave characteristics of an In0.53Ga0.47As/In0.52Al0.48As modulation-doped quasi-MISFET

The DC and microwave performance of a modulation-doped InGaAs/InAlAs quasi-MISFET structure, grown by molecular beam epitaxy, is reported. Improved performance is obtained with the incorporation of Ti in the source-drain metallisation with which contact resistances as low as 0.1 ?mm are measured. An extrinsic transconductance of 310mS/mm and a best value of fT=32 GHz in a 1.0 ?-gate device are measured at 300 K.     

Photoluminescence studies of In0.7Al0.3As/In0.75Ga0.25As/In0.7Al0.3As metamorphic heterostructures on GaAs substrates

The influence of the design of the metamorphic buffer of In_0.7Al_0.3As/In_0.75Ga_0.25As metamorphic nanoheterostructures for high-electron-mobility transistors (HEMTs) on their electrical parameters and photoluminescence properties is studied experimentally. The heterostructures are grown by molecular-beam epitaxy on GaAs (100) substrates with linear or step-graded In _x Al_{1 ? x} As metamorphic buffers. For the samples with a linear metamorphic buffer, strain-compensated superlattices or inverse steps are incorporated into the buffer. At photon energies ?ω in the range 0.6–0.8 eV, the photoluminescence spectra of all of the samples are identical and correspond to transitions from the first and second electron subbands to the heavy-hole band in the In_0.75Ga_0.25As/In_0.7Al_0.3As quantum well. It is found that the full width at half-maximum of the corresponding peak is proportional to the two-dimensional electron concentration and the luminescence intensity increases with increasing Hall mobility in the heterostructures. At photon energies ?ω in the range 0.8–1.3 eV corresponding to the recombination of charge carriers in the InAlAs barrier region, some features are observed in the photoluminescence spectra. These features are due to the difference between the indium profiles in the smoothing and lower barrier layers of the samples. In turn, the difference arises from the different designs of the metamorphic buffer.     

功率增益截止频率为183GHz的In0.53Ga0.47As/In0.52Al0.48As HEMTs

通过合理的外延层材料结构设计和改进的器件制备工艺,制备出功率增益截止频率（fmax）为183GHz的晶格匹配InP基In0.53Ga0.47As-In0.52Al0.48As HEMT。该fmax为国内HEMT器件最高值,还报道了器件的结构、制备工艺以及器件的直流和高频特性。     

A study of alloyed AuGeNi/Ag/Au based ohmic contacts on the Al0.48In0.52As/Ga0.47In0.53As system

Very low resistance alloyed NiGeAuAgAu ohmic contacts have been fabricated to the Al_0.48In_0.52As/Ga_0.47In_0.53As heterosystem. A thin capping layer of GalnAs was used to inhibit Al oxidation at the surface. Unlike NiGeAgAu ohmic metallization containing ≈;25% Ag commonly used for contacting GaAs based semiconductors at Cornell, the Ag concentraiton was reduced to ≈;10%. AES/sputtering depth profiles indicated that this allowed controlled dissolution of the nonconducting AlInAs top layer by the metallization which eventually interacted with the GalnAs without depleting it of In due to the strong Ag-In affinity. The stoichiometry of the conducting GalnAs, in contact with the reacted metals, was thus maintained and this yielded specific transfer resistances ≈;0.06 ohm · mm, the lowest to date.     

功率增益截止频率为183GHz的In0.53Ga0.47As/In0.52Al0.48As HEMTs

通过合理的外延层材料结构设计和改进的器件制备工艺,制备出功率增益截止频率(fmax)为183GHz的晶格匹配InP基In0.53Ga0.47As-In0.52Al0.48As HEMT.该fmax为国内HEMT器件最高值.还报道了器件的结构、制备工艺以及器件的直流和高频特性.