Pd-Ge contact to n-GaAs with the TiW diffusion barrier

Pd-Ge based ohmic contact to n-GaAs with a TiW diffusion barrier was investigated. Electrical analysis as well as Auger electron spectroscopy and the scanning electron microscopy were used to study the contact after it was subjected to different furnace and rapid thermal annealing and different aging steps. All analyses show that TiW can act as a good barrier metal for the Au/Ge/Pd/n-GaAs contact system. A value of 1.45 × 10⁻⁶ Ω-cm² for the specific contact resistance was obtained for the Au/TiW/Ge/Pd/n-GaAs contact after it was rapid thermally annealed at 425°C for 90 s. It can withstand a thermal aging at 350°C for 40 h with its ρ_c increasing to 2.94 × 10⁻⁶Ω-cm² and for an aging at 410°C for 40 h with its ρ_c increasing to 1.38 × 10⁻⁵ Ω-cm².     

Atmospheric and low pressure shadow masked MOVPE growth of InGaAs(P)/InP and (In)GaAs/(Al)GaAs heterostructures and quantum wells

The shadow masked growth technique is presented as a tool to achieve thickness and bandgap variations laterally over the substrate during metalorganic vapor phase epitaxy. Lateral thickness and bandgap variations are very important for the fabrication of photonic integrated circuits, where several passive and active optical components need to be integrated on the same substrate. Several aspects of the shadow masked growth are characterized for InP based materials as well as for GaAs based materials. Thickness reductions are studied as a function of the mask dimensions, the reactor pressure, the orientation of the masked channels and the undercutting of the mask. The thickness reduction is strongly influenced by the mask dimensions and the reactor pressure, while the influence of the orientation of the channels and the amount of undercutting is only significant for narrow mask windows. During shadow masked growth, there are not only thickness variations but also compositional variations. Therefore, we studied the changes in In/Ga and As/P ratios for InGaAs and InGaAsP layers. It appears that mainly the In/Ga-ratio is responsible for compositional changes and that the As/P-ratio remains unchanged during shadow masked growth.     

在p+GaAs体单晶材料上进行的NEA活化实验

NEA活化实验是利用体单晶材料进行的,未经任何外延或真空解理手续。为确立活化工艺,特别是表面清洁处理规范,作了相应AES分析。借助于测量样品附近高纯Al的熔点以校准及控制样品表面的温度。在不太好的本底真空(2×10^-7—6×10^-7Pa)条件下,活化好的GaAs样品之白光光电灵敏度可达1000μA/lm以上。     

激光二极管抽运的GaAs被动Q开关Nd：YVO4激光器

利用固体可饱和吸收体砷化镓（GaAs）作为被动调Q元件，实现了激光二极管抽运平－凹腔掺钕钒酸钇（Nd:YVO4）激光调Q运转，详细测量了砷化镓被动调QNd:YVO4激光输出特性，获得脉宽15ns，重复频率470kHz，光束质量M^2=1.31的激光输出，调Q激光运转阈值为500mW，并数值求解了砷化镓被动调Q速率方程，讨论了被动调Q机理以及调Q脉冲宽度和脉冲重复频率对抽运速率的依赖关系，理论计算结果与实验结果相一致。     

AlGaAs／GaAs HBT表面效应的二维数值分析

采用表面效应集总模型综合考虑表面费米能级钉扎和表面复合效应，对ＡｌＧａＡｓ／ＧａＡｓＨＢＴ表面效应的影响进行了二维数值模拟。结果表明，表面态的存在对集电极电流几乎不产生影响，但显著增加基极电流，使得电流增益明显下降。同时还发现在台面结构ＡＩＧａＡｓ／ＧａＡｓＨＢＴ中外基区表面复合的集边效应，即外基区表面复合主要发生在发射极台面与外基区的交界处附近，与外基区长度基本无关。模拟还表明基区缓变结构可以减少表面复合，提高电流增益。     

DX centers in AlxGa1-xAs bulk alloy,AlAs/GaAs ordered,and disordered superlattices

Properties of theDX centers in Al_0.5Ga_0.5As bulk alloy (b-AL), (AlAs)₂ (GaSa)₂ ordered superlattice (o-SL) and (AlAs) _m (GaAs) _n disordered superlattice (d-SL) (m = 1, 2, 3,n = 1, 2, 3) with the same macroscopic composition were measured and compared. By deconvolution of deep level transient spectroscopy (DLTS) spectrum due to theDX center, we have found a decrease in the number of separate peaks in DLTS spectrum in an intentionally atomic ordered arrangement. Visiting Scholar of the Japan Society for the Promotion of Science. On leave from Department of Electrical Engineering, San Jose State University, San Jose, California 95192-0084, USA.     

Crystallographic orientation dependence of the growth rate for GaAs low pressure organometallic vapor phase epitaxy

The complete crystallographic orientation dependence of the growth rate for GaAs low pressure organometallic vapor phase epitaxy (LPOMVPE) is determined using a previously described semi-empirical model. A set of LPOMVPE growth rate polar diagrams is presented for reactor temperatures near 550°C as well as near 700°C. Also, the variation of the growth rate polar diagrams as a function of process variables is given. The experimental data utilized in the semiempirical model was attained using a typical horizontal reactor LPOMVPE system and typical LPOMVPE process parameters.     

GaAs、GaP、InP、InGaAsP、AlGaAs、InAlGaAs的化学腐蚀研究

为研制全集成光开关、微片式激光器等，对ＧａＡｓ、ＧａＰ、ＩｎＧａＡｓＰ、ＩｎＡＩＧａＡｓ、ＡｌＧａＡｓ等材料的化学腐蚀进行了实验研究。为了研制ＩｎＡｌＧａＡｓ／ＩｎＡｌＡｓ／ＩｎＡｌＧａＡｓ微片式激光器，开发了Ｈ３ＰＯ４／Ｈ２Ｏ２／Ｈ２Ｏ薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ选择性腐蚀液；为了研制ＩｎＧａＡｓＰ／ＩｎＰ／ＩｎＧａＡｓＰＴｂａｒ型光波导，开发了ＨＣｌ／Ｈ３ＰＯ４／Ｈ２Ｏ２薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ２选择性腐蚀液；为了研制ＧａＰ、ＩｎＧａＰ光波导，开发了ＨＣｌ／ＨＮＯ３／Ｈ２Ｏ薄层腐蚀液。它们都具有稳定、重复性好、速率可控、腐蚀后表面形貌好等特点。除此之外，蚀刻成的ＧａＰ光波导侧壁平滑无波纹起伏。此种结果尚未见报导。     

Accurate measurement of capture cross sections in deep level transient spectroscopy: Application to EL2 in GaAs

A rigorous formulation of capacitance changes during trap filling processes is presented and used to accurately determine the electron capture cross section of EL2 in GaAs at a particular temperature, 377K, in this case. The value, σ_n (377K) = 2.7 × 10⁻¹⁶ cm², is compared with that predicted from the emission dependence.     

GaAs、InP集成电路技术的发展——1992年IEEE GaAs IC讨论会评述

本文介绍了1992年IEEE GaAs IC讨论会的概况,并依据这次国际会议所发表的论文,以GaAs、InP集成电路的技术路线为主线,介绍和评述了GaAs基PHEMT,HBT,MESFET以及InP基HEMT、HBT等集成电路的现状与发展。