Carrier compensation in O+ implanted n-type GaAs

Results of electrical measurements on 1 MeV O⁺ implanted n-type GaAs are reported. After annealing the implanted material it is found that the free carrier compenasation rate (k), defined by Favennec[1] as the number of carriers removed per oxygen atom, can be dependent upon both the starting material and the implanted dose.     

Effects of diffused nickel on the silicon-silicon dioxide interface

The effects of diffused nickel on the interface of silicon and a thermally grown oxide are examined. Information regarding effective fixed charge at the interface, surface state distribution and surface state type, is derived from capacitance-voltage characteristics of metal-oxide-semiconductor capacitors made with nickel doped and non-nickel doped silicon. Nickel doping is shown to reduce the density of effective surface states with energies more than 0·15 eV below E_i, and to remove effective charge at the interface of the order of 0·1 μC/cm².     

Effect of Yb^3＋ concentration on Er^3＋ luminescence properties of sol-gelderived silica-alumina xerogels

Er~(3 )-activated silicate glasses are recognized of tech-nological interest in several areas and,in particular ,it iswell known for their successful application in opticalamplification at the C band (1530 -1565 nm) of tele-communications[1].Inside this l…     

Effect of electron cyclotron resonance H+,Ne+, Ar+, and Xe+ plasma precleaning ontitanium silicide formation

A vacuum integrated cluster tool process incorporating electron cyclotron resonance plasma cleaning, Ti sputter deposition, and rapid thermal annealing in N₂ is used to form a TiN_x<1/TiSi_y bilayer on (100) Si where the film composition is controlled by the preclean chemistry. Chemical cleaning with nominal 10 eV H⁺ completely removes native Si oxide resulting in a hydrogen terminated surface that promotes silicidation compared to one cleaned with buffered-oxide-etching (BOE). If the native oxide is only partially reduced, viz., SiO_x<2 surface, for example by shortening the H⁺ exposure time, then silicidation is largely inhibited and a thicker nitride layer is formed. Sputter cleaning with 50 to 250 eV Ar⁺ results in a bilayer that is roughly equivalent to that formed with BOE, whereas 50 to 150 eV Xe⁺ bombardment favors nitridation. Precleaning with >150 eV Ne⁺ promotes silicidation, thereby minimizing nitride thickness. The effects of precleaning are significant as the activation energy for TiSi_y formation is reduced from 1.8 eV characteristic of a BOE cleaned surface to 1.2 eV on Si etched with 250 eV Ne⁺. Mechanistically, the silicide kinetics are shown to be inhibited by the presence of a thin amorphous layer that is formed only when cleaning Si with Ar⁺ and Xe⁺ with the effect that both knock-on oxygen atoms and implanted noble gas atoms trapped within the amorphous layer retard the requisite solid-phase epitaxial regrowth kinetics. Recrystallizing the amorphous Si surface prior to metallization appears to restore the near-normal silicide kinetics that is characteristic of Ne⁺ cleaning     

Collector-up HBT's fabricated by Be+and O+ion implantations

A novel collector-up (C-up) GaAs/AlGaAs heterojunction bipolar transistor (HBT) has been developed and initial device results presented. This device has its extrinsic base defined by Be + and O + implantations. The combination of Be + / O + implantations and heat-pulse annealing is leading to a considerable reduction in the parasitic current and capacitance in the extrinsic base region. Improved device structure and performance expected from this device are discussed in detail.     

Various effects of silicidation on shallow p+ junctionsformed by BF2+ implantation into thin poly-Sifilms on Si substrates

Various effects of silicidation on shallow p⁺ n junctions formed by the scheme that implants BF₂⁺ ions into thin poly-Si films on Si substrates are described. A post-Ni silicidation just slightly improves the preformed junctions of the annealed sample. However, as the sample is first deposited with thin Ni films after the implantation and then annealed, the resulting junctions are much better than the preformed ones. Moreover, as the sample is deposited with Ti films, the resultant junctions are just slightly better the preformed ones     

Effective recombination velocity at the NN+ interface

The effective recombination velocity S_nn⁺ at the nn⁺ interface in buried layer (nn⁺p) and n epi-n⁺ substrate structures has been studied using a model which takes into account the retarding outdiffusion region, recombination and bandgap narrowing. The variation of S_nn⁺ with diffusion length and bandgap narrowing has been estimated taking into consideration their doping-dependence. An attempt has been made to explain the wide range in the reported values for S_nn⁺ using the results of this study.Results indicate clearly the difference between the S_nn⁺ of the two structures. This difference arises from the collection by the p-substrate which accounts for a significant part of the S_nn⁺ of the buried layer structure over a wide range of values of diffusion length. This collection component of S_nn⁺ is sensitive to bandgap narrowing.On the other hand, the S_nn⁺ of the nn⁺ structure is largely determined by the recombination in the outdiffusion region which is sensitive mainly to the value of diffusion length in that region. The component of S_nn⁺ representing recombination in the n⁺ substrate is sensitive to bandgap narrowing. The present study indicates the dependence of S_nn⁺ on the structure and processing of the devices in which the nn⁺ interface occurs.     

Ag纳米颗粒对Er3+/Tm3+/Yb3+共掺铋锗酸盐玻璃上转换发光特性的影响

采用传统熔融淬冷法制备了系列Er³⁺/Tm 3+/Yb³⁺共掺复合Ag纳米颗粒的铋锗酸盐玻璃样品。从吸收光谱中 确定了Ag纳米颗粒表面等离子体共振(SPR)峰位于545nm附近;透射 电镜(TEM)图像中观察到均匀分布的Ag纳米颗粒,尺寸 约为6～18nm。研究了纳米Ag含量对Er3＋/Tm3＋ 共掺复合Ag纳米颗粒铋锗酸盐玻璃上转换发光特性的影响,结果表 明,Tm³⁺离子472nm处的上转换蓝光、Er³⁺离子525nm处的上转换绿光、543nm处的上转换 绿光和661nm处的上转换红光发光强度在AgCl含量的质量百分数为 1%时达到最大值,与未掺杂AgCl的基质玻璃相比,分别提高了约3.2、3.8、5.4倍。     

Improved microwave performance on low-resistivity Si substrates bySi+ ion implantation

Microwave characteristics of spiral inductors on low-resistivity Si substrates have been improved by implanting Si₂₈⁺ ions. Spiral inductors fabricated on these implanted substrates demonstrate better Q-value and microwave performance. The Q-value of inductor enhanced 60% on the implanted substrates than that of low resistivity Si substrates. An equivalent circuit model of inductor has been evaluated to discuss the effect of substrate loss     

Deep trapping of implanted Na+ and Li+ ions near the Si/SiO2 interface in metal-oxide-silicon structures

Na⁺ and Li⁺ ions have been implanted in the oxide layer of MOS structures with doses ranging from 3 × 10¹¹ to 3 × 10¹³ ions/cm². Part of the implanted ions can be retraced as mobile ions: this fraction decreased with increasing dose. The trapping of the mobile ions near the Si/SiO₂ interface has been investigated by means of the thermally stimulated ionic current (TSIC) technique. The average energy depth of the ionic traps appeared to increase with increasing dose. Moreover, we found that Li⁺ ions are trapped deeper than Na⁺ ions under equivalent experimental conditions. The influence of the applied electric field on the detrapping has been studied. In the case of 3 × 10¹³ Na⁺ implantation, the barrier lowering corresponds with the Poole-Frenkel theory. We have also paid attention to the effects of bias-temperature stress treatments on the trapping kinetics. We observed a decrease of the mobile ion current after long BTS treatments.     

Rapid thermal annealing effects on Si p+-n junctionsfabricated by low-energy FIB Ga+ implantation

Effects of rapid thermal annealing (RTA) on sub-100 nm p⁺ -n Si junctions fabricated using 10 kV FIB Ga⁺ implantation at doses ranging from 10¹³ to 10¹⁵ cm ^-2 are reported. Annealing temperature and time were varied from 550 to 700°C and 30 to 120 s. It was observed that a maximum in the active carrier concentration is achieved at the critical annealing temperature of 600°C. Temperatures above and below the critical temperature were followed by a decrease in the active concentration, leading to a `reverse' annealing effect     

CaSi2O2N2:Ce3+/Eu2+荧光粉的发光性能研究

采用高温固相反应法制备了CaSi₂O₂N₂:C e³⁺/Eu ²⁺荧光粉,研究了分别掺杂Ce³⁺、Eu²⁺及Ce³⁺/Eu²⁺共掺 杂时荧光粉 的发光特性。CaSi₂O₂N₂:Ce³⁺在333 nm激发下得到宽波段的发射谱,发射峰 位于395nm,随着Ce³⁺浓度的增大,发 射波长出现明显的红移,猝灭浓度为1mol%。CaSi₂O₂N₂:Eu²⁺在397nm激发下得到峰值位于540nm处的宽波段发射谱, 猝灭浓度为1mol%。对于Ca0.99－2xSi₂O₂N₂:xCe ³⁺,xLi⁺,0.01Eu²⁺荧光粉,在333nm激发下,位于395nm处的发射峰十分微 弱,在540nm处有宽带发射,随着Ce³⁺浓度增大,位于540nm处的Eu²⁺的特征 发射显著增强。对于Ca0.98－ySi₂O₂N₂: 0.01Ce³⁺,0.01Li⁺,yEu²⁺荧光粉,在激发光波长 为333nm,Eu²⁺浓度较低时,可以观察到两个发射带,峰值分 别位于395nm及540nm,随着Eu²⁺浓度增加,位于395nm的 发射强度一直减小,而540nm处的发射强度先增加后减小,猝灭浓 度为0.4mol%。证实了Ce³⁺,Eu²⁺之间发生了有效的能 量传递。计算出Ce 3+、Eu²⁺之间能量传递的效率ηT,在Eu²⁺浓 度为 1mol%时ηT趋于饱和,达到97.7%。通过计算,得到Ce3+ 与Eu²⁺之间的能量传递方式为电偶极-电偶极相互作用。     

Er3+-Yb3+ and Er3+ doped fiberlasers

Single-mode fiber lasers operating at ~1.57 μm are described. Output powers of >2 mW are reported for laser diode pumped operation. Direct comparison is made between fiber lasers using sensitized erbium (Er³⁺ and Yb³⁺) and erbium on its own. The performance of Er³⁺-Yb³⁺ fiber lasers is analyzed in more detail as a function of fiber length. Both CW and Q-switched operations are studied and the results obtained demonstrate that practical sources at 1.5 μm are available from diode pumped Er³⁺ -Yb³⁺ systems     

Er^3＋／Ce^3＋共掺碲铌酸盐玻璃的制备及光学特性研究

采用高温熔融退火法制备了系列75TeO2—10Nb2O5-10ZnO-5Na2O-0．5Er2O3-xCe2O3=（x=0．00,0．25,0．50,0．75,1．00mol％）和（75-y）TeO2-10Nb2O5-10ZnO～5Na2O～yB2O3—0．5Er2O3-0．75Ce2O3（y=2,5,10,15mol...     

基于PLD法制备ZnO:Eu3+,Li+薄膜的发光性质研究

采用脉冲激光沉积(PLD)技术在Si(111)衬底上生长了Eu3+、Li+共掺杂的ZnO薄膜。分别对样品进行了X射线衍射(XRD)谱测试和光致发光(PL)谱分析,重点研究了退火处理对样品结构和发射光谱的影响。XRD谱测试表明,样品具有很好的C轴择优取向。PL谱研究表明,当用325nm光激发样品时,样品的发射光谱仅由ZnO基质的紫外发射和蓝光发射组成,并没有发现稀土Eu3+的特征发光峰;样品的蓝光发射源于电子从Zn填隙形成的浅施主能级到Zn空位形成的浅受主能级跃迁;和真空中退火的样品相比,O2中制备的样品的蓝光发射减弱,紫外发光增强。用395nm的光激发时,退火前样品分别在594nm和613nm处存在两个明显的Eu3+特征发光峰,退火后的样品仅发现Eu3+位于594nm的特征发光峰,这表明,退火处理不利于稀土离子的特征发射,但O2中退火的样品ZnO基质红绿波段发射光谱明显增强。     

Ag纳米颗粒对Er3+/Yb3+共掺铋锗酸盐玻璃上转换发光性能的影响

采用熔融退火法制备了Er³⁺/Yb³⁺共 掺复合银(Ag)纳米颗粒的铋锗酸盐玻璃,对玻璃样品 进行物理性质、透射电镜(TEM)图像和光谱性能测试,分析了铋锗酸盐玻璃样品中Er³⁺的上转换 发光机理。研究表明:随着退火温度的增加,Ag纳米颗粒不断析出,绿光(527nm波长 )和红光(661nm波长)发光强度都得到了较大增强,在420℃时,上转换发光强度分别为未掺 杂AgCl时的4.45和4.22倍。其上转换发光增强的原因归结于Ag 纳米颗粒表面等离子体共振(SPR)导致局域场电场增强和Ag⁰→Er³⁺的能量转移。     

Er3+、Eu3+双掺杂LaOF荧光粉的光学性能研究及防伪应用

有机发光材料可能对人体或环境造成影响,除此之外还有生产成本高、发光易淬灭、发光强度与颜色不易于控制的缺点,因此探索性能优越的稀土发光材料并寻找其应用价值是具有重要意义的。本文基于水热辅助固相法制备出Er³⁺、Eu³⁺离子共掺杂LaOF荧光粉,通过X射线衍射仪(X-ray diffractometer, XRD)、扫描电镜(scanning electron microscope, SEM)和荧光分析仪对不同Er³⁺掺杂浓度下的LaOF∶Eu³⁺荧光粉体的相组成、粒径尺寸、形貌及荧光光谱进行表征与分析。结果表明：在900℃的温度下煅烧,物相由前驱体LaF₃转变为四方相LaOF,且随着Er³⁺掺杂浓度的升高,在365 nm与393 nm波长激发下均呈现出多色可调谐的发光特性,其中365 nm激发下呈现自橙色光向黄色光的转变,而在393 nm光辐射下则由橙色光向品红色光过渡。将Er³⁺、Eu³⁺共掺杂LaOF荧光粉制成...     

红色荧光粉YF3:Eu3+,Gd3+的制备及发光性能

采用水热法合成了YF₃:xEu³⁺和YF₃:0.14Eu³⁺,0.08Gd³⁺系列荧光粉。通过X射线衍 射(XRD)、 扫描电子显微镜(SEM)、光电子能谱(EDS)、光致发光(PL)和长余辉光谱分别对样品的物相、 结构、形貌、 表面元素、PL和荧光寿命进行了表征。XRD检测表明,合成的样品属正交晶系。ED数据验 证了合成样品的表面元素组分。PL光谱测试表明,YF₃:xE u³⁺的激发光谱由200～300nm的宽带和Eu³⁺ 的系列窄带激发峰组成,YF₃:0.14Eu³⁺,0.08Gd³⁺的 激发光谱由200～300n m的宽带和Eu³⁺,Gd³⁺的系列窄带 激发峰组成。在319nm紫外光激发下,测得YF₃:xEu³⁺ 材料的发射光谱为一个多峰谱,主峰位于593,3nm。 当Eu³⁺掺杂物质的量的浓度大于14%时,出现了浓度猝灭现象。在319nm紫外光激发下,YF₃:0.14Eu³⁺, 0.08Gd³⁺的发射光谱出现Eu³⁺的⁵D₀→⁷F₁ (593nm,橙光)、⁵D₀→⁷F₂(613nm,红光)跃迁发光峰,此时,Gd³⁺ 的掺杂能增强Eu³⁺的发光。通过色坐标分析可知,当激发波长为374nm时,YF₃: 0.14Eu³⁺的色坐标为 (0.337,0.239),是很好的红色发光粉。对YF ₃:xEu³⁺和YF₃:0.14Eu3+ ,0.08G d³⁺的荧光衰减曲线的拟合证实,存在Gd³⁺→Eu³⁺的能量传递。     

Ce3+对掺Er3+碲铌锌钠玻璃光谱性质的影响

用高温熔融法制备了摩尔组分百分比为75TeO₂- 10Nb₂O₅-10ZnO-5Na₂O-0.5Er₂O₃-xCe₂O₃(x=0.00、0.25、 0.50、0.75、1.00)的碲酸盐玻璃样品。测量了玻璃样品的吸收光谱、上转换 光谱、拉曼光谱和 荧光光谱。结合Judd-Ofelt(J-O)理论计算了玻璃样品的强度参数Ω_t(t=2、4、6)、自发辐射跃迁几率A、荧光分支比β和辐射寿命 τrad,并用McCumber理论计算得到了Er³⁺的受激发射截面。比 较了玻璃样品中Er³⁺的放大器带宽 品质因子(σpeak_e×FWHM)和增 益品质因子(σpeak_e×τm),分 析了Er³⁺/Ce³⁺间能量转移(ET)机 理以及Ce³⁺对上转换发光的抑制作用。研究表明,适量Ce³⁺的引入对于掺Er ³⁺碲铌锌钠玻璃的光谱特性有一定的提高作用。     

A model for doped-oxide-source diffusion with a chemical reaction at the silicon-silicon dioxide interface

A mathematical model for doped-oxide-source diffusion is proposed. In this model the concept of segregation of impurity at the silicon-silicon dioxide is used and also a constant of “rate limitation” is introduced through a chemical reaction at the interface.