GaAs和InP基HFET工艺中的选择腐蚀

综合了ＧａＡｓ和ＩｎＰ基ＨＦＥＴ工艺中选择腐蚀技术的有关报道,重点介绍了应用ＩＣＰ设备和气体组合ＢＣＩ＋ＳＦ６进行异质结材料组合的干法腐蚀实验,腐蚀后在显微镜和扫描电镜窗口平整干净、作迁移率测试等为法腐蚀的片子相比较没有看出差别,适宜用于器件工艺。     

1.3μm InGaAsP/InP长寿命激光器

本交报道精心外延及光刻腐蚀,使外延片质量提高,器件的光电特性得到改善。最低闽值电流I_(th)=17mA,外微分效率η=25%(单面),最高连续激射温度为130℃,最大输出功率超过40mW。采用PbSn焊料改进制管工艺,提高了器件的可靠性。器件在25℃时的中值寿命为26万小时。     

InGaAsP／InP掩埋条型激光器的漏电流分析

本文针对Ｐ－Ｎ－Ｐ－Ｎ埋区结构中的漏电流,用广义Ｐ－Ｎ－Ｐ－Ｎ三端器件的理论模型,细致地分析和模拟计算了Ｐ－Ｎ－Ｐ－Ｎ掩埋型ＢＨ激光器的漏电流特性,并据此给出了优化设计器件的数据曲线．通过具体的激光器工艺,我们做出的ＦＢＨ激光器的漏电流大大减小,激光器的线性输出光功率可高达２０ｍＷ,室温寿命超过１０万小时．     

全固源分子束外延生长InP和InGaAsP

在国产分子束外延设备的基础上,利用新型三温区阀控裂解源炉,对InP及InGaAsP材料的全固源分子束外延(SSMBE)生长进行了研究.生长了高质量的InP外延层,表面缺陷密度为65cm-2,非故意掺杂电子浓度约为1×1016cm-3.InP外延层的表面形貌、生长速率及p型掺杂特性与生长温度密切相关.研究了InGaAsP外延材料的组分特性,发现在一定温度范围内生长温度对Ⅲ族原子的吸附系数有较大影响.最后得到了晶格匹配的In0.56Ga0.4As0.04P06材料,低温光致发光谱峰位于1507 nm,FWHM为9.8 meV.     

InGaAsP／InP激光器非平面液相外延生长的研究

本文叙述了用于制作 InGaAsP/InP 半导体激光器的非平面液相外延工艺。讨论了各种因素对非平面液相外延生长的影响。在 InP 衬底上和刻有沟槽的 InGa-AsP/InP 外延片上成功地生长出了高质量外延层。用该外延片制作的激光器在室温连续工作条件下典型阈值电流30mA,典型输出功率为10mW。最高激射温度为115℃。     

全固源分子束外延生长InP和InGaAsP

在国产分子束外延设备的基础上 ,利用新型三温区阀控裂解源炉 ,对 In P及 In Ga As P材料的全固源分子束外延 (SSMBE)生长进行了研究。生长了高质量的 In P外延层 ,表面缺陷密度为 65cm- 2 ,非故意掺杂电子浓度约为 1× 1 0 16cm- 3.In P外延层的表面形貌、生长速率及 p型掺杂特性与生长温度密切相关 .研究了 In Ga As P外延材料的组分特性 ,发现在一定温度范围内生长温度对 族原子的吸附系数有较大影响 .最后得到了晶格匹配的 In0 .56Ga0 .4 4 As0 .94 P0 .0 6材料 ,低温光致发光谱峰位于 1 50 7nm,FWHM为 9.8me V.     

1.3μm InGaAsP／InP RWG型激光器的可靠性

通过对１．３μｍＩｎＧａＡｓＰ／ＩｎＰＲＷＧ型激光器的加速老化寿命试验，证明了此种结构激光器的可靠性，它在环境温度为５０℃、１００ｍＡＣＷ及环境温度为８０℃、１００ｍＡＣＷ的条件下加速老化，经过３２２０ｈ的实际测试共计１９３２００器件小时，在测试过程中没有一支器件失效。在这样的条件下其５０℃下的外推寿命ＭＴＴＦ为２０万ｈ，其统计标准偏差为σ＝１．０１６；８０℃下的外推寿命ＭＴＴＦ为３．８万ｈ，其统计标准偏差为σ＝０．８０４，从而推算出该结构激光器的退化激活能Ｅａ＝０．５４３ｅＶ，其２５℃下的寿命ＭＴＴＦ为１０３万ｈ。     

显示GaAs/AlGaAs缺陷的新方法——超声AB腐蚀

本文提出了一种采用超声 AB腐蚀方法显示 GaAs/AlGaAs单晶缺陷的新方法.该方法可以在自然光环境、常温下显示位错露头、位错线、层错、微沉淀及生长条纹等多种晶体缺陷,分辨率高,腐蚀坑形状规则,操作简便.     

InGaAsP／InP系选择性刻蚀技术

比较了用于ＩｎＧａＡｓＰ／ＩｎＰ系的几种腐蚀液的选择性刻蚀效果并给出了最佳选择性刻蚀条件。     

InP quantum dots in (1 0 0) GaP: Growth and luminescence

We describe the growth and optical emission from strained InP quantum wells and quantum dots grown on GaP substrates using gas-source molecular beam epitaxy. Self-organized quantum dot formation takes place for InP coverage greater than 1.8 monolayers on the (1 0 0) GaP surface. Atomic force and scanning-electron microscopy studies indicate that unburied dots have a lateral size of 60–100 nm and are about 20 nm high, with dot densities in the range of 2–6×10⁸ cm⁻² for InP coverage between 1.9 and 5.8 MLs. Intense photoluminescence is emitted from both the quantum wells and the quantum dots at energies of about 2.2 and 2.0 eV, respectively. Time-resolved measurements indicate rather long carrier lifetimes of about 19 ns in the quantum wells and about 3 ns in the quantum dots. The data indicate that the InP/GaP quantum wells form a type-II band system, with electrons in the X valleys of the GaP recombine with holes in the InP. Furthermore, in the InP/GaP quantum dot system, the conduction band edge in the X valley of the GaP is nearly aligned with that in the Γ valley of the InP. Rapid thermal annealing of the quantum dots results in at least a six-fold enhancement of integrated emission intensity as well as some Ga-In interdiffusion. The low interdiffusion activation energy indicates that the material near the interface between the GaP matrix and the InP dots is not free of defects.     

InGaAsP／InP异质结构材料组分及结构的XPS测定

采用Ｘ射线光电子能谱（ＸＰＳ）对ＩｎＧａＡｓＰ／ＩｎＰ异质结构ＭＯＣＶＤ外延晶片作了表面薄层元素、组分定性、定量和深度分布分析。利用ＸＰＳ组分定量数据与带隙和组分量数据与晶体常数的经验公式计算带隙、晶格常数和失配率，并与光压谱（ＰＶＳ）测定的带隙值和Ｘ射线双晶衍射（ＤＣＤ）测定的失配率作了比较，比较结果是满意的。实验和分析表明，在研究ＭＯＣＶＤ外延膜材料表面组分和表面点阵结构方面。     

Elastic and plastic contributions to X-ray Line broadening of InGaAsP/InP Heterostructures

The coherency state of MOCVD grown InGaAsP/InP double-heterostructure wafers was examined and their effects on the structural properties were determined in this study. Lattice mismatches were measured using {511} asymmetric and (400) symmetric x-ray reflections. The chemical lattice misfit and the elastic strain were also calculated. Misfit dislocations were examined by both x-ray topography and photoluminescence imaging. The x-ray full width at half maximum (FWHM) varied with the degree of mismatch. The largest FWHM was obtained for samples containing the misfit dislocations. It was found that FWHM is influenced not only by the plastic deformation, but also by the elastic strain. To model the dependence of the FWHM, the radius of curvature was measured, and its contribution to the x-ray line broadening was calculated. Also, the contribution from misfit dislocations was taken into account. This model assumes that the dislocations are planar and interact weakly with each other. Good agreement between measured and calculated values was obtained. Thus, it is concluded that the major contribution to x-ray line broadening ofelastically strained sample is the lattice curvature induced by misfit strain, and that the dominant factor affecting x-ray FWHM ofplastically deformed sample is lattice relaxation induced by misfit dislocation.     

Etching behavior of GaAs/AlGaAs multilayer structure during laser beam scanning

The thermochemical etching behavior of GaAs/AlGaAs multilayer structure during laser beam scanning has been studied. The etch rate changes between GaAs and AlGaAs epilayers as the etching process proceeds through the layered sample. The phenomenon can be explained by the difference of thermal parameters of the heterojunction interface. The local temperature rise from laser irradiation has been calculated to investigate etching characteristics for GaAs and AlGaAs. It is concluded that the good thermal confinement at GaAs/AlGaAs interface produces the wider etch width of GaAs layer than that of AlGaAs layer in GaAs/AlGaAs multilayer. The maximum etch rate of the GaAs/AlGaAs multilayer was 32.5 μm/sec and the maximum etched width ratio of GaAs to AlGaAs was 1.7.     

In-situ OMVPE process sensing of GaAs and AlGaAs by photoreflectance

The contactless electromodulation method of photoreflectance has been successfully applied as an in-situ sensor of the OMVPE process. The direct band gap,E ₀, of GaAs and AIGaAs has been measured, in-situ, under OMVPE growth conditions. To the best of our knowledge, this is the first report of an in-situ photoreflectance measurement of III-V materials properties in an OMVPE system. This is significant in that it illustrates the potential for the application of photoreflectance as an in-situ process monitor, analogous to the use of RHEED measurements in MBE. The GaAs substrate temperature of 650°, as measured by an optical pyrometer, corresponds to the temperature derived using the Varshni equation and published Varshni coefficients to within the error of the published data.     

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。     

Dopant incorporation in GaAs and AlGaAs grown by MOMBE for high speed devices

Continued improvement in GaAs/AlGaAs device technology requires higher doping levels, both to reduce parasitics such as source resistances, and to enhance speed in devices such as the heterostructure bipolar transistor (HBT). In this paper we will discuss doping issues which are critical to high speed performance. In particular, we will focus on doping of GaAs and AIGaAs using carbon as the acceptor and Sn as the donor. Due to the unique growth chemistry of metalorganic molecular beam epitaxy (MOMBE), both of these impurities can be used to achieve high doping levels when introduced from gaseous sources such as trimethylgallium (TMG) or tetraethyltin (TESn). Comparison of SIMS and Hall measurements show that both elements give excellent electrical activation to 1.5 × 10¹⁹ cm³ for Sn and 5 × 10²⁰ cm⁻³ for C. More importantly, we have found that both impurities canbe used to achieve high quality junctions, indicating that little or no diffusion or segregation is occurring during growth. Because of the excellent incorporation behavior of these dopants, we have been able to fabricate a wide range of devices including field effect transistors (FETs), high electron mobility transistors (HEMTs), and Pnp HBTs whose performance equals or exceeds that of similar devices grown by other techniques. In addition to these results, we will briefly discuss the key differences in growth kinetics which allow such abruptness and high doping levels to be achieved more readily in MOMBE than in other growth techniques.     

Photoreflectance spectroscopy of low-dimensional GaAs/AlGaAs structures

Results of room-temperature photoreflectance measurements on three GaAs/Al_0.33Ga_0.67As multiquantum well (MQW) structures with three different widths of wells and on two GaAs/Al_0.33Ga_0.67As high-electron-mobility transistor (HEMT) structures are presented. Energy-gap-related transitions in GaAs and AlGaAs were observed. The Al content in AlGaAs was determined. MQW transition energies were determined using the first derivative of a Gaussian profile of the measured resonances. In order to identify the transitions in the MQS, the experimentally observed energies were compared with results of the envelope function calculation method for a rectangular quantum well. The Franz–Keldysh oscillation (FKO) model was also used to determine the built-in electric field in various parts of the investigated structures. The values of the electric fields allow us to hypothesise about the origin of these fields. © 1997 John Wiley & Sons, Ltd.     

Hydrogen passivation of defects and impurities in GaAs and InP

Hydrogen passivation experiments in GaAs and InP are discussed. For GaAs it is argued that the results of hydrogen passivation of shallow donors, shallow acceptors and deep centers in materials with different Fermi level positions as well as diffusion data for undoped or lightly doped GaAs are consistent with the assumption that hydrogen is neutral or amphoteric (at least at rather high temperatures of treatment). Some new interesting effects are reported such as improvement of GaAs homogeneity as revealed by microcathodoluminescence imaging and also hydrogen passivation of surface states in GaAs. Evidence is presented that hydrogenation in direct plasmas leads to damage region formation at the surface of the GaAs. A new method of hydrogenation is described that is free from that drawback. The marked improvement of Au/n-GaAs Schottky diodes I-V characteristics is reported after using this method. This new technique is also used to hydrogenate InP for which conventional methods encounter very serious problems. In InP the results of hydrogen passivation experiments on shallow donors and acceptors imply that hydrogen is a deep donor. An interesting effect of injection annealing at room temperature of hydrogen-donor complexes inn-InP is observed.