SiGe材料的组分表征研究与退火分析

采用固相扩散法在n-Si (100) 衬底上制备了两组退火条件不同的SixGe1-x薄膜.利用椭圆偏振光谱和二次离子质谱技术,对薄膜的厚度及组分分布进行了表征,两者具有较好的一致性.分析了退火对薄膜厚度、组分和应变的影响.成功得到了完全驰豫状态的SixGe1-x薄膜,可用于实际器件制作.     

液相外延生长的Al_xGa_(1-x)As/GaAs异质结构的俄歇电子能谱

采用俄歇电子能谱仪(AES)对液相外延生长的GaAs-AlxGa_(1-x)As异质结构进行了研究.结果表明,在异质结界面处,有一过渡层,其组分由异质结的一边向另一边单调地变化,该层的厚度依赖于溶液的饱和度.还对样品表面的沾污情况进行了观测.     

二维MoS2(1-x)Se2x特性及其光电晶体管性能

表征了 MoS2(1-x)Se2x样品的Raman光谱和光致发光(PL)谱性质,验证了 MoS2(1-x)Se2x基于组分和厚度的带隙可调特性,并基于Raman光谱分析了单层及多层样品由于引入Se原子引起的结构变化及光谱特性.此外,受益于单层材料的直接带隙的电子结构,在405 nm激光波长、112.1 μW/cm2功率...     

HEMT太赫兹探测器的二维电子气特性分析

采用分子束外延技术(MBE)对GaAs/Al_xGa_(1-x)As二维电子气(2DEG)样品进行了制备,样品制备过程中,通过改变Al的组分含量、隔离层厚度、对比体掺杂与δ掺杂两种方式,在300 K条件下对制备的样品进行了霍尔测试,获得了室温迁移率7.205E3cm~2/Vs,载流子浓度为1.787E12/cm~3的GaAs/Al_xGa_(1-x)As二维电子气沟道结构,并采用Mathematica软件分别计算了不同沟道宽度时300 K、77 K温度下GaAs基HEMT结构的太赫兹探测响应率,为HEMT场效应管太赫兹探测器的研究和制备提供了参考依据.     

Si1-x Gex:C缓冲层的生长温度对Ge薄膜外延生长的影响

用化学气相淀积方法,在Si(100)衬底上生长Si1-x Gex:C合金作为缓冲层、继而外延生长了Ge晶体薄膜,用X射线衍射(XRD)、俄歇电子能谱(AES)、拉曼(Raman)衍射光谱等对所得到的样品进行了表征测量,着重研究了Si1-x Gex:C缓冲层生长温度对样品结构特征的影响.结果表明:Si1-x Gex:C缓冲层中的Ge原子浓度沿表面至衬底方向逐渐降低,其平均组分随着生长温度的升高而降低.这与较高生长温度(760～820℃)所导致的原子扩散效应相关;在Si1-x Gex:C缓冲层上外延生长的Ge薄膜具有单一的晶体取向,薄膜的晶体质量随着温度的升高而降低.     

用光截止法测量Hg_(1-x)Cd_xTe的横向组分均匀性

本文以相当可靠的黑体辐射公式为基础,利用Hg_(1-x)Cd_xTe样品本身的光截止特性测量样品的截止波长,再用E_g-x经验公式求出样品的组分(?)对样品进行二维扫描,获得了Hg_(1-x)Cd_xTe样品横向组分的面分布。测得的组分均方根偏差与电子探针的测量结果符合得很好。     

用光截止法测量Hg_(1-x)Cd_xTe的横向组分均匀性

本文提出一种测量Hg_(1-x)Cd_xTe横向组分均匀性的简便方法。该方法以相当可靠的黑体辐射公式为基础,利用Hg_(1-x)Cd_xTe样品本身的光截止特性,测量样品的截止波长,再用E_(?)-X经验公式求出样品的组分X。通过对样品的二维扫描,可求得Hg_(1-x)Cd_xTe横向组分的面分布。透光因子的定义     

基于离子束辅助沉积生长柔性类单晶硅的方法

通过离子束辅助沉积(IBAD)和射频磁控溅射(RFMS)的方法在低成本、柔性且轻质的金属箔基板上异质外延生长类单晶硅薄膜.在整个过程中,类单晶的Ge被用作晶格匹配的缓冲层进行Si的外延生长,其中Ge的基材来源于用IBAD法制备的双轴织构的氧化物过渡层.通过SixGe1-x的梯度溅射进行Ge与Si之间的过渡,减少其界面缺...     

液相外延生长的GaAs/Al_xGa_(1-x)As异质结构的俄歇电子谱研究

我们采用俄歇电子能谱仪对液相外延生长的GaAs—Al_xGa_(1-x)As异质结构进行了研究。结果表明:在异质结界面处有一过渡层,其组分由异质结的一边向另一边单调地变化,过渡层的厚度依赖于溶液的饱和度。还对外延片表面的沾污情况进行了观测分析。     

用喇曼光谱表征锗硅应变层超晶格

对Ge_xSi_(1-x)/Si超晶格的喇曼光谱研究表明,这类样品中各层间的应力分配取决于缓冲层组分。合金层中的Ge—Si峰峰移δω随组分x或应变ε作线性变化。对Ge_n/Si_n(n为原子层数)超晶格的喇曼光谱研究表明,在n=4的超薄层超晶格中,锗硅界面互混程度较小,并发现样品的生长温度对其质量有决定性影响。     

Sample preparation of GaN-based materials on a sapphire substrate for STEM analysis

In this work, a detailed TEM sample preparation recipe based on a wedge polishing technique for GaN-based materials is presented. The obtained samples have atomically flat surfaces without any obvious surface damages such as the formation of amorphous layers. A composition estimation of Al(x)Ga(1-x)N from Z-contrast STEM imaging is carried out using these samples. The results are in good accord with the nominal composition.     

分子束外延生长的Ge_xSi_(1-x)/Si应变超晶格的X射线衍射研究(英文)

The structural properties of GexSi1-x/Si strained-layer superlattices grown by molecular beam epitaxy are investigated using conventional X-ray θ-2θ scans with a scintillation counter. The experimental diffraction curves for the small-angle reflection and symmetric Bragg reflection are analyzed by applying the optical mutilayer theory and a approach of the dynamical theory of X-ray diffraction for distorted crystals. The structure parameters of superlattices can be obtained without Fourier transformation or computer fitting. The theoretical fit of the experimental diffraction curves yields detailed information on the strain profile,the chemical composition, and the thickness of individual layers of superlattices, which provides a powerful tool to evaluate the structural perfection of GexSi1-x/Si strained-layer superlattices.     

SPRITE探测器的电阻问题

ＳＰＲＩＴＥ探测器的电阻是一个重要的器件参数。研究了Ｈｇ１－ｘＣｄｘＴｅ材料组分和电阻率、芯片厚度和表面电导等因素对该电阻的影响，并就实验数据进行了比较结果表明：ＳＰＲＩＴＥ器件的室温电阻主要是受Ｈｇ１－ｘＣｄｘＴｅ材料组份和芯片厚度的影响。而其液氮温度电阻则主要是受芯片表面电导的影响。     

Characterization of GaNxAs1-x Alloy Grown on GaAs by Molecular Beam Epitaxy

Ga Nx As1 - x,the combination of small amount of nitrogen and Ga As,has beenexperimentally observed with the band gaps several hundreds me V lower than that ofGa As[1～ 4] .The alloy has attracted considerable attention in the applicat...     

Characterization of GaNxAs1-x Alloy Grown on GaAs by Molecular Beam Epitaxy

The GaNxAs1-x alloy has been investigated which is grown on GaAs (100) substrate by molecular beam epitaxy with a DC-plasma nitrogen source. The samples are characterized by high resolution X-ray diffraction (HRXRD) and low temperature photoluminescence (PL) measurements. Both HRXRD and PL measurements demonstrate that the crystalline and optical qualities of GaNxAs1-x alloy degrade rapidly with the increase of N composition. The nitrogen composition of 4.5 % can be obtained in GaNxAs1-x/GaAs quantum well by optimizing growth conditions,through which a photoluminescence peak of 1201nm is observed at a low temperature (10 K). The dependence of GaNxAs1-x band gap energy on the nitrogen composition in this investigation corresponds very well with that of the theoretical one based on the dielectric model when considering the effect of the strain. At the same time,we also demonstrate that the bowing parameter of GaNxAs1-x alloy is composition dependent.     

Ge_xSi_1-x/Si异质结构的近红外吸收光谱测量

测量分析了采用 RRH/VLP—CVD 方法外延生长的 Ge_xSi_(1-x)/Si 异质结构中 Ge_xSi_(1-x)合金薄层的近红外吸收光谱。由谱线计算出 Ge_(0.15)Si_(0.85)与 Ge_(0.45)Si(0.55)合金层的带隙分别为1.02eV 和O.88eV,与相同组分的体合金一致。结果表明用红外吸收光谱测量研究异质结构薄层材料的能带结构及带隙是一种准确、简便的方法。     

Si-SiGe材料三维CMOS集成电路技术研究

根据SiGe材料的物理特性,提出了一种新有源层材料的三维CMOS集成电路.该三维CMOS集成电路前序有源层仍采用Si材料,制作nMOS器件;后序有源层则采用SiGe材料,以制作pMOS器件.这样,电路的本征性能将由Si nMOS决定.使用MEDICI软件对Si-SiGe材料三维CMOS器件及Si-SiGe三维CMOS反相器的电学特性分别进行了模拟分析.模拟结果表明,与Si-Si三维CMOS结构相比,文中提出的Si-SiGe材料三维CMOS集成电路结构具有明显的速度优势.     

AlGaN /GaN分布布拉格反射镜的MOCVD生长

文中利用MOCVD方法,采用高质量GaN作为缓冲层,在（0001）取向的蓝宝石衬底上实现了不同组分的AlxGa1-xN/GaN分布布拉格反射镜（DBR）的制备.通过XRD、SEM、AFM、反射谱等测量分析手段,研究了AlxGa1-xN/GaN DBR的结构质量、厚度和表面形貌.     

Si-SiGe材料三维CMOS集成电路技术研究

根据SiGe材料的物理特性,提出了一种新有源层材料的三维CMOS集成电路.该三维CMOS集成电路前序有源层仍采用Si材料,制作nMOS器件;后序有源层则采用SiGe材料,以制作pMOS器件.这样,电路的本征性能将由Si nMOS决定.使用MEDICI软件对Si-SiGe材料三维CMOS器件及Si-SiGe三维CMOS反相器的电学特性分别进行了模拟分析.模拟结果表明,与Si-Si三维CMOS结构相比,文中提出的Si-SiGe材料三维CMOS集成电路结构具有明显的速度优势.     

Improved 634 nm MQW AlGaInP LEDs performance with novel tensile strain barrier reducing layer

Light-emitting diodes (LEDs) under long-term or high-current operating undergo significant performance change and degradation with time. Thus a novel Ga/sub x/In/sub 1-x/ P tensile strain barrier reducing (TSBR) structure is grown between window and cladding layers of multi-quantum-well-AlGaInP LEDs. The TSBR (/spl sim/ 150 AGa/sub x/In/sub 1-x/P) film is of lattice size and valence band energy intermediate between those of window and cladding layers, thus reducing band offset. Experimental characterization shows significant decrease in device forward bias, dynamic resistance and junction heating, with strong improvement in power output degradation for the high current region. Various compositions of Ga/sub x/In/sub 1-x/P TSBR are fabricated, aged at dc 50 mA, and tested at nonradiative and radiative current levels. Optimal Ga/sub x/In/sub 1-x/P composition is determined. Two separate power output degradation mechanisms are noted and discussed. In sum, the TSBR layer appears a highly successful design for improved power efficiency, reliability and global lifetime behavior of an LED-type device.