Al/GaAs界面反应的XPS研究

用XPS研究了清洁无序GaAs表面沉积超薄Al膜后的界面反应,结果表明,原沉积于GaAs表面的Al能进入GaAs衬底取代Ga形成AlAs,而通过Al-Ga替位反应释放出来的Ga则残留在衬底表面,提出了Ga/AlAs+GaAs/GaAs三层结构模型。 关键词：     

磷化镓单晶外延工艺及其自支撑薄膜的制作

采用Ga—PCI_3—H_2系统开管式汽相外延的方法,在GaAs衬底上生长掺Zn的GaP单晶。经化学腐蚀去掉GaAs衬底得到自支撑GaP单晶薄膜。 研究了在P型GaAs衬底上外延P—型GaP的生长条件,生长速度与温度的关系,生长速度与输运气体中的PCI_3浓度的关系,以及晶向偏差,清洁条件等对外延层质薄的(井彡)响。     

GaAs光电阴极片原子级表面清洁方法的研究及评价

本文对GaAs光电阴极片UHV系统中原子级表面清洁方法做了研究,它们是:光加热法、直接加热法、离子轰击加退火法、热子加热法,表面清洁效果用装于UHV系统中间在线俄歇检测,表面质量用Aa/GaAuger峰高进行比较,指出两种用于第三代象增强器光电阴极的表面清洁方法:CS-离子轰击加退火法和热子背加热法。     

GaAs阴极光电发射特性北大核心CSCD

采用氧过量YOYO激活工艺对经高温清洁的砷化镓(GaAs)晶片进行激活,测量其量子效率和在激光及背景光照射下的使用寿命,得到了4.66%的量子效率;在电子枪中的实验获得了平均流强大于1mA的束流。分析了真空度、高温清洁温度、铯氧激活工艺等因素对GaAs光阴极初始量子效率和使用寿命的影响。     

NEA GaAs光电阴极激活工艺研究

本文报道了 GaAs 反射式光电阴极的激活工艺过程和结果.通过实验确定了 GaAs表面的热清洁温度,利用钼丝热辐射加热方法达到了比较理想的清洁效果,采用铯分子源和高纯氧作氧源获得了高于1000μA/1m 的激活积分灵敏度.     

S钝化GaAs(100)表面的电子特性

用TB-LMTO方法研究单层的S原子在理想的GaAs (100) 表面的化学吸附, 对GaAs(100)表面是Ga-和As-中断两种情况分别进行考虑. 计算了S原子在不同位置的吸附能、吸附体系与清洁的GaAs(100)表面的层投影态密度, 以及电子转移情况. 结果表明, 两种情况下S原子都是桥位吸附最稳定, S-Ga相互作用比S-As稍强, S钝化GaAs(100)表面可以取得明显的钝化效果.     

与玻璃粘结的GaAs-AlGaAs透射式光阴极

在GaAs基底上已做出GaAs—GaAlAs—GaAs—GaAlAs异质结构,它与corning7056玻璃粘结,基底GaAs以及在基底GaAs上面的AlGaAs用化学方法腐蚀掉,腐蚀GaAs与AlGaAs的腐蚀剂分别为NH_4OH—H_2O_2与HF溶液。GaAs—AlGaAs玻璃结构具有特别好的形态、厚度均匀和透射式光电发射性能好的特点。     

7056玻璃与大面积GaAs外延片粘接工艺分析

介绍7056窗玻璃与大面积GaAs外延片的牯接工艺,并分析了GaAs片的表面形状、氮化硅的厚度、组分及粘接前的清洁处理工艺对粘接质量的影响。着重讨论了压力、温度和加热速率三者之间内在联系及其选取范围,给出了粘接工艺的调整和控制方法。     

半导体异质结界面能带排列的实验研究

本文综述半导体异质结界面能带排列的实验研究情况。介绍了九种目前已成功用于这方面研究的实验方法,这包括C—V测试、光致发光谱测量和光电子能谱测量,并讨论了Al_xGa_(-x)As/GaAs、InAs/GaSb、Ge/Si和Ge/GaAs等几种典型系统的一些研究结果。     

半导体异质结界面能带排列的实验研究

本文综述半导体异质结界面能带排列的实验研究情况。介绍了九种目前已成功用于这方面研究的实验方法,这包括C—V测试、光致发光谱测量和光电子能谱测量,并讨论了Al_xGa_(-x)As/GaAs、InAs/GaSb、Ge/Si和Ge/GaAs等几种典型系统的一些研究结果。     

XPS data for sputter-cleaned In0.53Ga0.47As,GaAs, and InAs surfaces

Core level binding energies and Auger parameters were determined for In, Ga, and As in the three compounds In_0.53Ga_0.47As, GaAs, and InAs. The surfaces were cleaned by 1.5 keV Ar ion bombardment. Under this condition the radiation-induced defects are small. In the case of GaAs the Ga and As3d levels become comparable with available data for chemically cleaned surfaces. The high Ga deficiency of chemically cleaned In_0.53Ga_0.47As surfaces could not be observed. Sputter cleaned surfaces seem to be closer to the bulk composition.     

Observation of oxygen contamination at ZnSe/GaAs interfaces using SIMS

ZnSe epilayers were grown on GaAs (1 0 0) substrates using MBE. The native contamination (oxide and carbon) was removed in situ from the substrate surfaces by conventional thermal cleaning and by exposure to atomic hydrogen. A maximum substrate temperature of 600 °C was required for the thermal cleaning process, while a substrate temperature of 450 °C was sufficient to clean the substrate using hydrogen. ZnSe epilayers were also grown on As capped GaAs epilayers, which were decapped at a maximum temperature of 350 °C. SIMS profiles showed the existence of oxygen at the interface for all of the substrate preparation methods. The oxygen surface coverage at the interface was found to be 0.03% for the atomic hydrogen cleaned substrate and 0.7% for the thermally cleaned substrate.     

Electrical properties of metal-GaAs Schottky barriers

Schottky barrier contacts have been fabricated by vacuum evaporation of thin films of six different metals (Mg, In, Al, Au, Bi and Sb) onto chemically cleaned n-type GaAs substrates. Bi and Sb contacts on GaAs have been reported for the first time. The contacts were examined for their C-V and I-V characteristics. The diodes exhibit near ideal characteristics for all the metals with values of the ideality factor n ranging from 1.06 to 1.1. The values of the barrier height obtained from C-V measurements could be brought into agreement with those obtained from I-V measurements only when the ideality factor was also included in the expression of the saturation current. By employing the most recent and reliable values of metal work function φ_M, the dependence of barrier height on φ_M has been investigated and an estimate of the surface state density and the Fermi level at the GaAs surface has been made. The surface state density obtained from this analysis is significantly larger than that reported by previous workers.     

Growth of catalyst-free GaAs nanowire with As pulse injection for full zinc-blende structure

Full zinc-blende structure GaAs nanowire grown by a catalyst-free method is reported with As pulse injection in the initial growth time. When As is injected by a pulse while maintaining Ga injection, high Ga supersaturation could easily form nanowire nucleation for the seed formation. Then, continuous GaAs injection contributes to GaAs nanowire growth for increasing length. The GaAs nanowire could grow further with 3.7-μm length and 120-nm diameter. GaAs nanowires were measured by transmission electron microscopy analysis.     

An application of half-terrace model to surface ripening of non-bulk GaAs layers

In order to predict the actual quantity of non-bulk GaAs layers after long-time homoepitaxy on GaAs （001） by theo- retical calculation, a half-terrace diffusion model based on thermodynamics is used to calculate the ripening time of GaAs layers to form a fiat morphology in annealing. To verify the accuracy of the calculation, real space scanning tunneling microscopy images of GaAs surface after different annealing times are obtained and the roughness of the GaAs surface is measured. The results suggest that the half terrace model is an accurate method with a relative error of about 4.1%.     

二维光子晶体T型波导分支器数值模拟研究

采用平面波展开法和时域有限差分法,对GaAs二维正方晶格光子晶体的色散特性和带隙结构进行了数值模拟研究,并对GaAs二维光子晶体线缺陷构成的T型波导分支器的微波传输特性进行了模拟和优化。数值模拟结果表明,光子晶体填充比对带隙结构有显著地影响。通过在拐角处插入额外的电介质棒对GaAs二维正方光子晶体T型波导分支器进行优化,数值模拟的结果表明,优化的GaAs二维正方光子晶体T型波导分支器在一阶带隙范围内透射系数将提高到0.96以上。     

透射式GaAs光阴极的静电键合粘结

提出了用于GaAs光阴极粘结的静电键合方法.相比于传统的热粘结方法,该方法温度低（350℃）,时间短（5 min）,在空气中进行.所制得的GaAs光阴极在激活台内的峰值灵敏度为68.8 mA/W（峰值波长为830 nm）.以此制作的三代微光管的积分灵敏度为1 311 μA/lm,优于传统的热粘结工艺制作的微光管的灵敏度(～1 200 μA/lm).     

优质GaAs/Si和AlGaAs/Si材料的MOCVD生长研究

用自制常压MOCVD装置,在Si衬底上生长GaAs和AlGaAs外延层,在高温去除Si衬底表面氧化膜之后,采用两步法,即低温生长过渡层,再提高温度生长外延层。得到了表面镜面光亮的优质GaAs和AlGaAs外延层。X射线双晶衍射仪测试GaAs外延层,其回摆曲线半峰宽是200孤秒,GaAs和AlGaAs外延层在77K温度下,PL谱半峰宽分别是17meV和24meV。     

Al/GaAs表面量子阱界面层的原位光调制反射光谱研究

用分子束外延（MBE）方法在GaAs表面量子阱上外延生长不同厚度的Al层，以超高真空下的原位光调制光谱（PR）作为测量手段，研究Al扩散形成的表面势垒层对于GaAs表面量子阱中带间跃迁峰位和峰形的影响.根据跃迁峰的变化，采用有效质量近似理论计算出了Al和GaAs 的互扩散长度为0.5nm，这是半导体工艺中的一个重要常数. 关键词： Al GaAs 原位光调制反射光谱（PR） 分子束外延（MBE）     

硒化锌的气相外延生长

采用改进的气相外延法在(100)GaAs衬底上外延生长了ZnSe单晶膜。最大生长速率为每小时10μm左右。淀积过程的激活能为10kcal/mol。在77K的温度下测量了外延膜的光致发光,4460Å附近可以观察到很强的蓝色发射。外延膜的电阻率～1.1Ω·cm。