MIMO和智能天线技术的结合

4G的主要关键技术有：MIMO技术，智能天线技术，OFDM技术，调制与编码技术，全IP网络技术，Ad Hoc无线网络技术，软件无线电技术等。MIMO技术可以提高系统的信道容量，提高信息传输速率；而智能天线技术可以提高接收信号的信干比和小区的用户容量，自提出以来就深受关注，已被TD—SCDMA标准采用，国际电联也明确将其作为第三代及其以后移动通信技术发展的主要方向。     

无线通信技术的新动向及发展趋势

本文介绍了无线通信技术的发展动向及未来趋势,指出数字化技术、码分多址技术、微蜂窝技术、语音寻呼、个人通信网、多媒体通信等是无线通信技术的发展方向。     

多业务一体化解决方案的技术比较

本文分析比较了多路复用技术、帧中继技术和IP技术，并提出了在建设一体化多业务平台时运用这三项技术的观点。     

信息高速公路的XDSL接入技术

首先简要介绍xDSL技术的发展情况;然后对HDSL,SDSL,ADSL,VDSL等技术通过分析对比,作简明扼要的阐述;最后简单介绍其使用现状和应用前景。在技术分析的基础上阐明：xDSL技术的发展,将使Internet接入真正跨上信息高速公路。     

化学技术在微机械传感器发展中的应用

微机械传感器除运用在微电子制造技术外,大量应用化学腐蚀,特种高分子落膜材料,电镀和电化学工艺等化学领域的技术,形成了很多独特的微机械加工技术,这些技术的运用解决了很多关键性技术问题,极大地推进了微机械传器技术的发展,本文从体微机械加工,表面微机械加工和LIGA技术三方面论述化学在近来新型传感器发展中的技术突破和成果。     

蓝芽技术与产品的发展

随着新世纪的到来,通信技术如雨后春笋般小断涌现,蓝芽作为一种短距离无线连接技术,正有力的推动第三代移动通信技术的迅速发展,到2000年12月为止,已有2047位会员加入蓝芽联盟。篮芽技术是现存网络和小型外围设备接门的连接桥梁,为现有固定网络基础设施提供专用和特定的无线连接方案。     

光子技术与光力技术--21世纪光子时代展望

以激光技术,光纤技术等为代表的众多现代光电子技术的发展,使传统的光学技术已进入了光电子技术时代。人们预测,随着各种各样的光子器件的研制成功,21世纪将成为光子时代,光子时代的基本构成是光子技术与光力技术以及由此而形成的光子工业和光力工业,本文介绍了光子技术和光力技术的基本概念及它们的框架技术。     

Shallow p+n junctions formed by using a two-stepannealing scheme with low thermal budget

Shallow p⁺n junctions have been formed by directly implanting BF₂ dopant into the Si substrate and then treating the samples by an annealing scheme with low thermal budget. A junction leakage smaller than 10 nA/cm² can be achieved by an annealing scheme that employs low-temperature long-time furnace annealing (FA) at 600°C for 3 h followed by medium-temperature rapid thermal annealing (RTA) at 800°C for 30 s. No considerable dopant diffusion is observed by using this low-thermal-budget annealing process. In addition, a moderate low-temperature annealing time of about 2-3 h should be employed to optimize the shallow p⁺n junction formed by this scheme. However, the annealing process that employs medium-temperature RTA followed by low-temperature FA treatment produces worse junctions than the annealing scheme that employs long-time FA at 600°C followed by RTA at 800°C     

Composite TaSi2/n+poly-Si formation by rapid thermal annealing

Composite TaSi2/n+ poly-Si structures have been formed by rapid thermal annealing (RTA). Polysilicon films 0.2 µm thick were deposited on oxidized Si wafers by LPCVD and heavily doped with phosphorus by diffusion. A layer of TaSix0.22 µm thick was then cosputtered on polysilicon from separate targets. The as-deposited samples were annealed by RTA using high-intensity tungsten lamps. Uniform stoichiometric low-resistivity tantalum disilicide was formed by RTA in 1 s at 1000°C. The sheet resistance and grain size of the silicide layers are comparable to those formed by conventional furnace anneals. The surface morphology of the RTA samples is superior to that obtained by furnace annealing. These results show that RTA technique has a great potential for low-resistivity tantalum silicide formation in VLSI circuits.     

升温速率对Bi_(0.98)La_(0.02)FeO_3-PbTiO_3薄膜结构性能的影响

采用sol-gel法在SiO2/Si(100)衬底上制备了0.68(Bi0.98La0.02)FeO3-0.32PbTiO3(BLFPT)薄膜。采用快速退火技术,以2～40℃/s速率升温、在700℃下保温100s对BLFPT薄膜进行了后续处理。研究了升温速率对BLFPT薄膜结构性能的影响。XRD测试结果显示BLFPT薄膜为赝立方结构。SEM和AFM结果表明,当升温速率为2℃/s时,BLFPT薄膜表面晶粒更为均匀致密,粗糙度最小。XPS分析显示,Bi、Fe和Ti分别主要以化合态Bi2O3、Fe2O3和TiO2的形式存在。     

注硅不掺杂半绝缘GaAs中的深能级缺陷

用DLTS法对经两步快速热退火(RTA)后的注硅不掺杂SI-GaAs中的缺陷进行了研究。确定了激活层中存在着两个电子陷阱组(以主能级ET1、ET2标记)及其电学参数的深度分布。在体内,ET1=Ec0.53eV,n=2.310-16cm2;ET2=Ec0.81eV,m=9.710-13cm2;密度典型值为NT1=8.01016cm-3,NT2=3.81016cm-3;表面附近,ET1=Ec0.45eV,NT1=1.91016cm-3;ET2=Ec0.71eV,NT2=1.21016cm-3,分别以[AsiVAs,AsGa]和[VAsAsiVGaAsGa]等作为ET1和ET2的缺陷构型解释了它们在RTA过程中的行为。     

Rapid Thermal annealing of si implanted GaAs

Rapid thermal annealing (RTA) with incoherent light from tungsten lamps shows high potential relative to the conventional furnace annealing (FA) to activate the implanted dopant. Due to the short time annealing, it could completely eliminate the re-diffusion of dopant and host atom. For the Si implantation with dose of 2 × 10¹⁴ cm², the electrical activity of 78% for RTA was higher than that of the FA. But for this short time, some defects measured by deep level transient spectroscopy (DLTS) were hard to remove. A two-step annealing was suggested by the combination of high temperature RTA (1000° C) and FA (700° C). After the post-FA, the defects would be removed to a great extent, and the electrical activity of dopant also increased. With the dose of 2 x 1013 cm^-2, the activity attained after the two step annealing was 92.5%, which may be the highest value according to our knowledge for rapid thermal annealing on Si ion implanted GaAs.     

两步快退火改善InP（Fe）中MeV硅注入层的品质

２ＭｅＶ、（１～２）×１０１４ｃｍ－２硅离子注入ＳＩ－ＩｎＰ（Ｆｅ）造成负的（－３．４×１０－４～－２．９×１０－４）晶格应变，光快速退火的激活能为０．２６ｅＶ。８８０℃／１０ｓ退火可得到１００％的施主激活。间断两步退火（３７５℃／３０ｓ＋８８０℃／１０ｓ）使注入层单晶恢复完全，较大程度（２０％～３５％）地改善了载流子的迁移率。四能量叠加注入已能在０．５～３．０μｍ的深度区域形成满足某些器件要求的低电阻（７．５Ω）高浓度［（２～３）×１０１８ｃｍ－３］的ｎ型导电层。     

快速退火对Pt/BST/Pt电容器结构和性能的影响

采用脉冲激光沉积(PLD)法在Pt/Ti/SiO2/Si(001)基片上制备了Ba0.6Sr0.4TiO3(BST)薄膜,对Pt/BST/Pt电容器在空气中进行400℃快速退火(RTA)处理,研究了快速退火对Pt/BST/Pt电容器的结构和性能的影响。结果表明:快速退火虽然对BST薄膜的结晶质量影响较小,但却极大改善了Pt/BST/Pt电容器的电学性能。当测试频率为100kHz、直流偏压为0V时,介电损耗从快速退火前的0.07减小到0.03,介电常数和调谐率略有增加。快速退火后负向漏电流过大现象得到了明显抑制,正负向漏电流趋于对称,在300×103V/cm电场强度下,漏电流密度为4.83×10–5A/cm2。     

Rapid thermal annealing of neutron transmutation doped silicon

Rapid thermal annealing (RTA) of neutron transmutation doped Si wafers is shown to be an alternative to conventional furnace annealing. Measurements of resistivity and deep level transient spectroscopy (DLTS), demonstrated annealing on wafers with diameters up to 75 mm. A 4.5 kW incoherent-light RTA furnace was used. Evidence for crystalline slip was found but this did not appear to affect the results. The slip was more severe for the larger diameter wafers. Some results from a DLTS examination of a partially rapid-thermal-annealed wafer are presented.     

Rapid thermal annealing of si implanted gaas

Rapid thermal annealing (RTA) technology offers potential advantages for GaAs MESFET device technology such as reducing dopant diffusion and minimizing the redistribution of background impurities. LEC semi-insulating GaAs substrates were implanted with Si at energies from 100 to 400 keV to doses from 1 × 10¹² to 1 × 10¹⁴/cm². The wafers were encapsulated with Si₃N₄ and then annealed at temperatures from 850-1000° C in a commercial RTA system. Wafers were also annealed using a conventional furnace cycle at 850° C to provide a comparison with the RTA wafers. These implanted layers were evaluated using capacitance-voltage and Hall effect measurements. In addition, FET’s were fabricated using selective implants that were annealed with either RTA or furnace cycles. The effects of anneal temperature and anneal time were determined. For a dose of 4 × 10¹²/cm² at 150 keV with anneal times of 5 seconds at 850, 900, 950 and 1000° C the activation steadily increased in the peak of the implant with overlapping profiles in the tail of the profiles, showing that no significant diffusion occurs. In addition, the same activation could be obtained by adjusting the anneal times. A plot of the equivalent anneal times versus 1/T gives an activation energy of 2.3 eV. At a higher dose of 3 × 10¹³ an activation energy of 1.7 eV was obtained. For a dose of 4 × 10¹² at 150 keV both the RTA and furnace annealing give similar activations with mobilities between 4700 and 5000 cm²/V-s. Mobilities decrease to 4000 at a dose of 1 × 10¹³ and to 2500 cm²/V-s at 1 × 10¹⁴/cm². At doses above 1 × 10¹³ the RTA cycles gave better activation than furnace annealed wafers. The MESFET parameters for both RTA and furnace annealed wafers were nearly identical. The average gain and noise figure at 8 GHz were 7.5 and 2.0, respectively, for packaged die from either RTA or furnace annealed materials.     

Photoreflectance and electrical characterization of Si-implanted GaAs

Si-implanted semi-insulating GaAs was studied by the photoreflectance (PR) technique and electrical analysis. Different energies and doses were used for Si implantation in two groups of samples. Subsequently, different rapid thermal annealing (RTA) conditions were utilized for one group of samples to optimize the damage removal and impurity activation. A significant annealing temperature dependence of the electrical activation and damage removal was observed. The 120 keV Si implantation introduced two impurity-like transitions in the PR spectra at photon energies about 40 meV and 100 meV from the band-edge. The 180 keV implantation introduced two impurity-like signals with energies about 50 meV and 65 meV from the band-edge which could be removed by RTA. Particularly, the 950‡ C, 10s RTA can totally remove the 65 meV signal caused by the 180 keV implantation. Samples exhibiting good PR signal also produced diodes from which electrical data was superior to the other cases.