基于MOCVD的InP/GaAs异质外延生长

使用金属有机物气相沉积方法(MOCVD),在GaAs衬底上生长InP外延层.先在GaAs衬底上生长一层低温InP缓冲层,然后再生长InP外延层.通过比较不同缓冲层生长条件下的外延层晶体质量,发现在生长温度为450℃,厚度约15nm的缓冲层上外延所得到的晶体质量最理想;此外,外延层厚度的增加对其晶体质量有明显改善作用.实验在优化生长条件的同时,也考虑了热退火等辅助工艺,最后所获得的外延层的双晶X射线衍射(DCXRD)的ω/2θ扫描外延峰半高全宽(FWHM)值为238.5".     

基于MOCVD的InP/GaAs异质外延生长

使用金属有机物气相沉积方法(MOCVD),在GaAs衬底上生长InP外延层.先在GaAs衬底上生长一层低温InP缓冲层,然后再生长InP外延层.通过比较不同缓冲层生长条件下的外延层晶体质量,发现在生长温度为450℃,厚度约15nm的缓冲层上外延所得到的晶体质量最理想;此外,外延层厚度的增加对其晶体质量有明显改善作用.实验在优化生长条件的同时,也考虑了热退火等辅助工艺,最后所获得的外延层的双晶X射线衍射(DCXRD)的ω/2θ扫描外延峰半高全宽(FWHM)值为238.5".     

基于异变缓冲层与应变层超晶格的InP/GaAs异质外延

利用低压金属有机化学气相沉积技术, 开展InP/GaAs异质外延实验。由450 ℃生长的低温GaAs层与超薄低温InP层组成双异变缓冲层, 并进一步在正常InP外延层中插入In1-xGaxP/InP(x=7.4%)应变层超晶格。在不同低温GaAs缓冲层厚度、应变层超晶格插入位置及应变层超晶格周期数等条件下, 详细比较了InP外延层(004)晶面的X射线衍射谱, 还尝试插入双应变层超晶格。实验中, 1.2 μm和2.5 μm厚InP外延层的ω扫描曲线半峰全宽仅370 arcsec和219 arcsec; 在2.5 μm厚InP层上生长了10周期In0.53Ga0.47As/InP 多量子阱, 室温PL谱峰值波长位于1625 nm, 半峰全宽为60 meV。实验结果表明, 该异质外延方案有可能成为实现InP-GaAs单片光电子集成的一种有效途径。     

InP/GaAs异质外延及异变InGaAs光探测器制备

借助超薄低温InP缓冲层,在GaAs衬底上生长出了高质量的InP外延层,在InP外延层中插入了15周期In0.93Ga0.07P/InP应变层超晶格(SLS),进一步阻断了失配位错穿透到晶体表面,提高了外延层的晶体质量,这样2.5 μm厚InP外延层的双晶X射线衍射(DCXRD)ω扫描半高全宽(FWHM)值降低至219 arcsec,该InP外延层的室温光荧光(PL)谱线宽度仅为42 meV.在此基础上,只利用超薄低温InP缓冲层技术就在半绝缘GaAs衬底上成功地制备出了长波长异变In0.53Ga0.47As PIN光电探测器,器件的台面面积为50 μm×50 μm,In0.53Ga0.47As吸收层厚度为300 nm,在3 V反偏压下器件的3 dB带宽达到了6 GHz,在1 550 nm波长处器件的响应度达到了0.12 A/W,对应的外量子效率为9.6%.     

用于光电集成的GaAs/InP MESFET研究

提出了一种新的生长过渡层的方法，并利用低压金属有机气相外延技术在InP衬底上生长出高质量GaAs外延材料，用X射线双晶衍射测得5μm厚GaAs外延层的（004）品面行射半高峰宽（FWHM）低至140arcsee。并制出GaAs金属半导体场效应晶体管（MESFET），其单位跨导为100mS／mm，可满足与长波长光学器件进行单片集成的需要。     

GaAs衬底上InP的直接外延生长及性能表征

用低压金属有机物气相外延(LP-MOCVD)技术,采用低温缓冲层生长法,在GaAs(100)衬底上直接生长了高质量的InP外延层.1.2 μm InP(004)面X射线衍射(XRD) ω-2θ和ω扫描半高全宽(FWHM)分别为373 arcsec和455 arcsec,在外延层中插入10周期Ga0.1In0.9P/InP应变超晶格后,其半高全宽分别下降为338 arcsec和391 arcsec.透射电子显微镜(TEM)测试显示,应变超晶格有效地抑制了失配位错穿进外延层,表明晶体质量得到了较大提高.     

Si_(1-x)Ge_x/Si多层异质外延结构的研究

对制作的 Ｓｉ１－ｘＧｅｘ／Ｓｉ多层异质外延结构进行了研究。并对其做了反射高能电子衍射（ＲＨＥＥＤ）、Ｘ射线衍射（ＸＲＤ）和扩展电阻（ＳＲ）等测量,给出了利用这种结构研制出的异质结双极晶体管（ＨＢＴ）的输出特性曲线。     

InP基MOCVD及MBE外延生长HBT的制备与分析

设计并研制了用于光电集成(OEIC)的InP基异质结双极晶体管(HBT),介绍了工艺流程及器件结构。分别采用金属有机化学气相沉积(MOCVD)及分子束外延(MBE)生长的外延片,并在外延结构、工艺流程相同的条件下,对两种生长机制的HBT直流及高频参数进行和分析。结果表明,采用MOCVD生长的InP基HBT,直流增益为30倍,截止频率约为38GHz;MBE生长的HBT,直流增益达到100倍,截止频率约为40GHz。这表明,MBE生长的HBT外延层质量更高,在相同光刻条件下,所对应的HBT器件的性能更好。     

LP—MOCVD生长InGaAlP外延层In组分控制的动力学分析

本文分析了低压转盘MOCVD生长室中气流的流动特征,首次提出了在高温（700℃左右）下生长InGaAlP外延层时,抑制In组分脱吸附的“动压力模型”,解释了托盘转速和生长压力等生长参数对In组分控制的影响。     

用于单片集成光接收机前端的GaAs基InP/InGaAs HBT

实现了一种可用于单片集成光接收机前端的GaAs基InP/InGaAs HBT。借助超薄低温InP缓冲层在GaAs衬底上生长出了高质量的InP外延层。在此基础上,只利用超薄低温InP缓冲层技术就在半绝缘GaAs衬底上成功制备出了InP/InGaAsHBT,器件的电流截止频率达到4.4GHz,开启电压0.4V,反向击穿电压大于4V,直流放大倍数约为20。该HBT器件和GaAs基长波长、可调谐InP光探测器单片集成为实现适用于WDM光纤通信系统的高性能、集成化光接收机前端提供了一种新的解决方法。     

Inx—Ga1—xAs／GaAs应变量子阱光学性质

研究了用分子束外延方法生长在GaAs(100)衬底上的In_xGa_(1-x)As/GaAs(x=0.1)应变多量子阱样品,观察了其光荧光谱和光调制反射谱的光谱结构,讨论了有关基态光跃迁和激发态光跃迁性质.根据实验结果给出了能带偏移比值为Q_c=0.69(Q_v=1-Q_c=0.31),并提出有关轻空穴束缚于GaAs层而形成Ⅱ类超晶格的重要佐证.     

LP-MOCVD grown (lnAs)m(GaAs)m short period superlattices on InP

(InAs)_m(GaAs)_m (1 ≤ m ≤ 12) short period superlattices (SPSs) have been grown on semi-insulated InP substrates with a 200 nm InP cap layer using low pressure metalorganic chemical vapor deposition (MOCVD). According to double crystal x-ray diffraction and transmission electron microscopy results, the critical layer thickness of (InAs)_m(GaAs)_m SPS was observed to be ～30Å (m = 5). For the SPS below the critical layer thickness, mirror-like surface morphology was found without defects, and strong intensity Fourier transformed photoluminescence (FT-PL) spectra were also obtained at room temperature. The SPS with m = 4 showed a drastic improvement in photoluminescence intensity of order of two compared to an InGaAs ternary layer. However, the SPS with a large value of m (m ≥ 6), rough surface was observed with defects, with broad and weak FT-PL spectra. The surface morphology of SPS was greatly affected by the substrate orientation. The SPS with m = 5 was grown on two degree tilted substrate from (100) direction and showed poor surface morphology as compared to the one grown on (100) exact substrate Moreover, the SPS grown on a (111)B substrate showed a rough triangular pattern with Nomarski optical microscopy. In-situ thermal annealed SPS with m = 4 showed a 18 meV increase in PL peak energy compared to the as-grown sample due to phase separation resulting from thermal interdiffusion.     

基于硼酸溶液处理的GaAs/InP低温晶片键合技术

提出了一种基于硼酸溶液的GaAs/InP低温晶片键合技术,实现了GaAs/InP基材料间简单、无毒性的高质量、低温(290℃)晶片键合。GaAs/InP键合晶片解理截面的扫描电子显微镜(SEM)图显示,键合界面整齐,没有裂缝和气泡。通过键合过程,InP上的In0.53Ga0.47As/InP多量子阱结构转移到了GaAs基底上。X射线衍射及荧光谱显示,键合后的多量子阱晶体质量未变。二次离子质谱(SIMS)和Raman光谱图显示,GaAs/InP键合晶片的中间层厚度约为17 nm,界面处B元素有较高的浓度,键合晶片的中间层很薄,因此可以得到较好的电学、光学特性。     

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.     

Analysis of V/III incorporation in nonstoichiometric GaAs and InP films using SIMS

Using secondary ion mass spectrometry (SIMS), we have investigated the excess group V content in GaAs and InP films grown by molecular beam epitaxy at low temperature. Using the inherent depth profiling capability of SIMS, we investigated the V/III ratio in films grown at nominally constant temperatures and also in films grown with stepped temperature profiles. Thickness profiles of the V/III ratio show the effects of intentional temperature changes and of an unintentional drift in the actual substrate temperature during growth. The ability to measure as little as 0.1% excess As and about 0.2% excess P indicates excellent measurement resolution. SIMS analysis is also used to identify a narrow growth temperature range over which InP can be grown with appreciable nonstoichiometry yet remain monocrystalline.     

Elastic strains in heteroepitaxial ZnSe1−xTex on InGaAs/InP (001)

Here we report on the elastic strains in ZnSe_1−xTe_x (x<0.9) epitaxial layers grown using photo-assisted metalorganic vapor phase epitaxy on In_0.53Ga_0.47As/InP (001) substrates. High-resolution x-ray diffraction was used to determine their composition and strain. At room temperature, we observed an apparent asymmetry in strains for tensile and compressive layers. However, when we accounted for the difference in thermal expansion between the substrate and epitaxial material, the growth temperature strain relaxation appears symmetric with respect to the sign of mismatch. The growth temperature strains are in agreement with the Matthews and Blakeslee (MB) model [J.W. Matthews and A.E. Blakeslee, J. Cryst. Growth 27, 118 (1974)] for both compressive (x>0.6) and tensile (x<0.4) layers. However, for the layers with composition in the range 0.4<x<0.6, the growth temperature strains exceed the values predicted by the MB theory. Apparently, low-mismatch layers experience a kinetic barrier to relaxation. The overall behavior can be fit by the relaxation model of Dodson and Tsao [B.W. Dodson and J.Y. Tsao, Appl. Phys. Lett. 51, 1325 (1987)] using the values Cμ²=80 s⁻¹ and γ₀=10⁻⁹.     

Metalorganic vapor phase epitaxial growth and structural characterization of GaAs/InP heterostructures

Highly mismatched GaAs epitaxial layers with thickness ranging from 15 nm to 7 μm have been grown on InP substrates by atomospheric pressure metalorganic vapor phase epitaxy. Layers thinner than 30 nm exhibited 3-D growth mechanism; in the thicker layers, the islands coalesced and then the growth followed the layer by layer mechanism. The elastic strain and the extended defects have been studied by high resolution x-ray diffraction and transmission electron microscopy, respectively. The common observation of planar defects, misfit, and threading dislocations in the layers has been confirmed. The results on the elastic strain release have been discussed on the basis of the equilibrium theory.