掺Sb的ZnO单晶的缺陷和性质研究

采用化学气相传输法生长了掺Sb的ZnO体单晶,生长温度为950℃.与非掺ZnO单品相比,掺Sb后ZnO单晶仍为n型,其自由电子浓度明显升高.x射线光电子能谱(XPS)测量结果表明.掺人的Sb在ZnO单晶中可能占据了Zn位,或处于间隙化置,形成了施主.利用光致发光谱(PL)测量发现掺Sb后ZnO单晶发出蓝光,该蓝色荧光与浅施主有关.这些结果表明在高温生长条件下,掺Sb后ZnO单晶中产生了高浓度的施主缺陷,因而难以获得P型材料.     

磷扩散氧化锌单晶的性质

分别在550和800℃对CVT方法生长的非掺ZnO单晶进行闭管磷扩散. 通过Hall测试、X射线光电子谱（XPS) 、光致发光（PL）以及喇曼散射对扩散后的样品进行测试分析. 发现扩散掺杂后的ZnO单晶仍显示n型导电性,自由电子浓度比非掺样品增高,在800℃扩散后尤为明显. PL测试结果表明,掺杂样品在420~550nm范围的可见光发射与缺陷有关. XPS测试表明:在550℃掺杂,P原子更易代替Zn位;在800℃扩散时,P未占据Zn位,而似乎占据了O位. 最终在磷扩散后的ZnO单晶中形成了高浓度的浅施主缺陷,造成了自由电子的显著增加.     

磷扩散氧化锌单晶的性质

分别在550和800℃对CVT方法生长的非掺ZnO单品进行闭管磷扩散.通过Hall测试、X射线光电子谱(XPS)、光致发光(PL)以及喇曼散射对扩散后的样品进行测试分析.发现扩散掺杂后的ZnO单晶仍显示n型导电性,自由电子浓度比非掺样品增高,在800℃扩散后尤为明显.PL测试结果表明,掺杂样品在420～550nm范围的可见光发射与缺陷有关.XPS测试表明:在550℃掺杂,P原子更易代替Zn位;在800℃扩散时,P未占据Zn位,而似乎占据了O位.最终在磷扩散后的ZnO单晶中形成了高浓度的浅施主缺陷,造成了自由电子的显著增加.     

非掺杂LEC-InAs单晶的残留杂质与电学性能研究

有关非掺InAs单晶中的施主杂质、缺陷及其产生规律的尚不清楚。本文利用辉光放电质谱（GDMS）定量分析了LEC法生长的InAs单晶的残留杂质,结合Hall测量、Raman散射和红外吸收等研究了施主杂质的来源和缺陷对材料性质的影响。     

PLD法制备锑掺杂p型ZnO薄膜

采用脉冲激光沉积方法在石英衬底上生长了掺锑(Sb)的p型ZnO薄膜.X射线衍射测试表明薄膜具有c轴择优取向的结构特性,霍尔测试表明ZnO薄膜呈p型导电特性,XPS分析表明Sb掺入了ZnO薄膜,且Sb掺人ZnO中是占据Zn的位置,而不是O的晶格位置.通过优化温度获得了电学性能优良的p型ZnO薄膜,其电阻率为2.21Ω·cm,迁移率为1.23cm2/(V·s),空穴浓度为2.30×1018cm-3.     

PLD法制备锑掺杂p型ZnO薄膜

采用脉冲激光沉积方法在石英衬底上生长了掺锑(Sb)的p型ZnO薄膜.X射线衍射测试表明薄膜具有c轴择优取向的结构特性,霍尔测试表明ZnO薄膜呈p型导电特性,XPS分析表明Sb掺入了ZnO薄膜,且Sb掺人ZnO中是占据Zn的位置,而不是O的晶格位置.通过优化温度获得了电学性能优良的p型ZnO薄膜,其电阻率为2.21Ω·cm,迁移率为1.23cm2/(V·s),空穴浓度为2.30×1018cm-3.     

MOCVD生长P型GaN的掺Mg量的研究

使用MOCVD技术在Al2O3衬底上生长了GaN：Mg薄膜.通过对退火后样品的光电性能综合分析,研究了掺Mg量对生长P型GaN的影响.结果表明：要获得高空穴载流子浓度的P型GaN,Mg的掺杂量必须控制好.掺Mg量较小时,GaN：Mg单晶膜呈现N型导电,得不到P型层;掺Mg量过大时,会形成与Mg有关的深施主,由于深施主的补偿作用,得不到高空穴浓度的P型GaN.生长P型GaN的最佳Cp2Mg/TMGa之比在1/660-1/330之间     

MOCVD生长P型GaN的掺Mg量的研究

使用 MOCVD技术在 Al2 O3衬底上生长了 Ga N∶ Mg薄膜 .通过对退火后样品的光电性能综合分析 ,研究了掺 Mg量对生长 P型 Ga N的影响 .结果表明 :要获得高空穴载流子浓度的 P型 Ga N,Mg的掺杂量必须控制好 .掺 Mg量较小时 ,Ga N∶ Mg单晶膜呈现 N型导电 ,得不到 P型层 ;掺 Mg量过大时 ,会形成与 Mg有关的深施主 ,由于深施主的补偿作用 ,得不到高空穴浓度的 P型 Ga N.生长 P型 Ga N的最佳 Cp2 Mg/TMGa之比在 1 /660— 1 /330之间     

退火温度对掺氮ZnO薄膜结构和光电特性的影响

采用Zn3N2热氧化法在直流磁控溅射设备上制备了掺氮ZnO薄膜（ZnO：N）,研究了不同退火温度对样品结构和光电特性的影响.X射线衍射谱（XRD）结果表明,Zn3N2在600℃以上退火即可转变为ZnO：N薄膜.X射线光电子能谱（XPS）发现,在热氧化法制备的ZnO：N薄膜中,存在两种与N相关的结构,分别是N原子替代O（受主）和N2分子替代O（施主）,这两种结构分别于不同的退火温度下存在,并且700℃下退火的样品在理论上具有最高的空穴浓度,这一点也由霍尔测量结果得到证实.同时,从低温PL光谱中观察到了与No受主有关的导带到受主（FA）和施主-受主对（DAP）的跃迁,并由此计算出热氧化法制备的ZnO：N薄膜中的No受主能级位置.     

PVT生长掺V SiC单晶的扫描电镜二次电子像衬度

在用SEM观察沿单晶生长方向切割掺V SiC晶片时,发现其二次电子像存在衬度。表现为先生长部分较明亮,后生长部分较暗淡,中间存在明显突变。在用PVT生长掺V SiC单晶时,SiC单晶中同时含有浅施主N和深受主杂质V是补偿半导体。从补偿半导体载流子浓度计算出发,建立了二次电子像衬度与载流子浓度的对应关系,很好解释了这一实验现象。结果表明,SiC单晶生长过程中随着浅施主N的减少,n型载流子的浓度逐步减少;当其浓度与V相当时,载流子浓度突变,可瞬间减少10个量级,此后又缓慢减少。正是这种载流子的突变引发了扫描电镜二次电子像衬度。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.