FTIR研究快中子辐照直拉硅中的VO2

快中子辐照直拉硅(CZ-Si)经400-450℃热处理后，空位-双氧复合体(VO2)是其主要的缺陷．在300-500℃热处理快中子辐照的CZ-Si后，IR光谱中有919．6cm^-1和1006cm^-1两个吸收峰伴随VO2(889cm^-1)出现，这两个IR吸收峰是VO2的一种亚稳态缺陷(O-V-O)引起的，此缺陷态是由一个VO(A中心)与次临近的一个间隙氧原子(Oi)相互作用所形成的．在300℃延长退火时间或升高退火温度，都会使(O-V-O)转变为稳态VO2．辐照剂量在10^19数量级，经400-450℃热处理所形成的缺陷主要为多空位型，而VO2被抑制．     

高温退火后非掺杂磷化铟材料的电子辐照缺陷

对不同气氛下高温退火非掺杂磷化铟(InP)材料的电子辐照缺陷进行了研究. 除铁受主外，磷化铁(FeP₂)气氛下退火后的InP中辐照前没有深能级缺陷，而辐照后样品的热激电流谱(TSC)中出现了5个较为明显的缺陷峰，对应的激活能分别为0.23 eV, 0.26 eV, 0.31 eV, 0.37 eV和0.46 eV. 磷(P)气氛下退火后InP中的热生缺陷较多，电子辐照后形成的缺陷具有复合体特征. 与辐照前相比，辐照后样品的载流子浓度和迁移率产生显著变化. 在同样的条件下，经FeP₂ 气氛下高温退火后的InP样品的辐照缺陷恢复速度较快. 根据这些现象分析了缺陷的属性、快速恢复机理和缺陷对材料电学性质的影响. 关键词： 磷化铟 电子辐照 缺陷     

FTIR研究快中子辐照直拉硅中的VO2

快中子辐照直拉硅(CZ-Si)经400—450℃热处理后，空位_双氧复合体(VO₂)是其 主要 的缺陷.在300—500℃热处理快中子辐照的CZ_Si后，IR光谱中有919．6cm^-1和 1006cm^-1两个吸收峰伴随VO₂(889cm^-1)出现，这两个IR吸收 峰是VO₂的一种亚稳态缺陷(O-V-O)引起的，此缺陷态是由一个VO(A中心)与次临近的一个 间隙氧原子(O_i)相互作用所形成的.在300℃延长退火时间或升高退火温度，都 会使(O -V-O)转变为稳态VO₂.辐照剂量在10¹⁹数量级，经400—450℃热处 理所形成的缺陷主要为多空位型，而VO₂被抑制.     

快速退火后重掺硼的分子束外延层的电学特性

对快速退火后用共蒸发Ｂ_２Ｏ₃方法实现重掺杂硼的硅分子束外延层的电学特性进行了研究．１１００℃退火可以使得外延层中载流子浓度提高４倍，空穴的霍耳迁移率与相同浓度下硅体材料的水平相当；外延层与衬底之间载流子浓度转变陡峭，获得了晶体质量良好的外延层． 关键词：     

浅杂质注入LEC半绝缘GaAs γ射线辐照缺陷

用深能级瞬态谱（ＤＬＴＳ）和恒温电容瞬态等技术研究了浅杂质注入ＬＥＣ半绝缘ＧａＡｓ的γ射线辐照缺陷。在Ｂｅ－Ｓｉ共注的ＬＥＣ半绝缘ＧａＡｓ中，γ射线辐照引入一电子陷阶Ｅ₂，并且大大增强了原有的Ｅ₀₁（０．２９８）和Ｅ₀₂（０．３４１）等缺陷，同时明显地瓦解了原有的少子陷阱Ｈ₀₃。在单纯注Ｓｉ的ＬＥＣ半绝缘ＧａＡｓ中，γ射线辐阳引进了Ｅ＇₀₁（０．２１６），Ｅ＇₀₂（０．３４１），Ｅ＇₂，Ｅ＇₄和Ｅ＇₅（０．６０８）等缺陷。其中Ｅ₀₁和Ｅ＇₀₁是新发现的和γ辐照有关的ＧａＡｓ缺陷。和低阻衬底同质外延ＧａＡｓ相比，Ｂｅ－Ｓｉ共注ＬＥＣ半绝缘ＧａＡｓ具有较低的γ射线辐照缺陷引入率，与此相反，单纯注Ｓｉ的ＬＥＣ半绝缘ＧａＡｓ具有较高的γ射线辐照缺陷的引入率。 关键词：     

(Bi,Pb)2Sr2Ca2Cu3Oy单相样品的超导电性与载流子浓度

对(Bi,Pb)₂Sr₂Ca₂Cu₃O_y单相样品进行不同条件下的热处理,通过X射线衍射、电阻-温度关系、交流磁化率,以及Hall系数等测量,发现样品均具有较好的单相性,随着热处理条件的变化,其超导转变中点温度(T_c)有规律地分布在100—110K之间,T_c随载流子浓度(n_H)的增加而升高。实验结果表明,热处理条件对样品的相结构、超导 关键词：     

氢离子注入对硅单晶电子辐照缺陷和氢泡形成的影响

以50keV和100keV能量的氢离子注入p型(100)直拉硅单晶薄膜。注入剂量为10¹⁵—2×10¹⁷H⁺/cm²。试样在HU-1300型超高压透射电子显微镜中进行电子辐照和原位加热动态观察。结果表明在20—300℃温度范围内与未注氢硅相比,注氢硅在相同的电子辐照条件下产生的电子辐照缺陷较少,电子辐照缺陷形成所需的潜伏时间较长。在电子显微镜中加热试样时于190℃开始观察到氢泡,190—220℃范围内氢泡逐渐产生并长大 关键词：     

在H2气氛中Bi2Sr2CaCu2O8+δ的热处理效应

对高品质单相多晶Bi₂Sr₂CaCu₂O_8+δ样品作真空或H₂气氛中不同温度下的热处理。由X射线结构分析,其正常态和超导态性质(特别是载流子浓度)的系统测量结果表明:Bi₂Sr₂CaCu₂0_8+δ样品在H₂气氛中热处理,其氧的释放可分为两个阶段:一是Bi-O层之间的过量氧原子的逸出,降低系统的载流子浓度,从而调节T_c;二是CuO₂面内氧原子的迁移,产生氧空位,使CuO₂面内Cu²⁺的短程二维反铁磁(2D-AFM)有序背景遭到破坏。可以认为:以往文献中报道的Bi₂Sr₂CaCu₂O_8+δ超导体的吸氢效应导致T_c的变化,很可能主要的并不是氢原子的电子掺杂行为,而是与吸氢过程中氧含量的变化相联系。 关键词：     

高温氧化多孔硅的电子束辐照效应

通过高温氧化处理得到的多孔硅,其阴极射线发光谱呈现明显的三峰结构。峰强随电子束辐照时间而下降。对光致发光很弱的样品,电子束辐照后光致发光明显地增强。红外透射谱及Raman谱分析表明样品基本上成为SiO_x.进一步分析指出三峰可能来源于SiO_x中的缺陷中心发光。电子束辐照在SiO_x禁带中引进了一些缺陷能级,通过这些能级使得紫外线可激发样品发光,出现光致发光增强的现象。     

富锌条件下生长氮掺杂氧化锌薄膜的光学和电学性质

报道了采用等离子体辅助分子束外延方法(P-MBE),利用NO作为N源和O源,在c-面蓝宝石(c-Al₂O₃)衬底上外延生长了N掺杂ZnO薄膜。X射线衍射谱(XRD)和吸收谱中都出现了不同于未掺杂样品的特性,X射线光电子谱(XPS)中也发现了N的受主信号。但是在霍尔效应(Hall-effect)测量中,发现该样品并没有出现预期的p型导电特性,而是出现载流子浓度很高(2.15×10²⁰cm^-3)的n型导电特性。结合XPS结果和理论分析,认为在富Zn条件下生长会导致过量的填隙Zn原子,补偿了全部的受主后,又促使其出现了从半导体-金属的Mott转变。     

Studies of annealing of point defects and their influence on the electrical degradation and recovery behaviors of heavily neutron irradiated silicon

We have investigated the annealing behaviors of point defects and their influence on the electrical degradation and recovery of heavily neutron irradiated silicon. It is found that high concentrations of divacancy (V₂) and vacancy-oxygen (VO) complexes are introduced in heavily irradiated silicon, which is responsible for the enhanced carrier recombination and therefore the observed drastic decrease of carrier lifetime. While the dopants deactivation from vacancy-phosphorus (VP) complexes and carrier compensation from VO and V₂ complexes result in the remarkable increase of resistivity. After post-irradiation isochronal annealing at 200–400°C the carrier lifetime and resistivity exhibit insignificant changes, which is attributed to the transformation of V₂ and VO complexes into [VO?+?O_i], V₂O, V₃O complexes at 200–300°C and the possible formation of VP-O complexes at 400°C. While the heat treatments at elevated temperatures (>400°C) result in the elimination of the majority of electrically active V_mO_n and the possible VP-O complexes, and therefore the carrier lifetime and resistivity of silicon begin to recover at 500°C and 650°C, respectively. However, the recovery of carrier lifetime is incomplete, which is due to the enhanced carrier-recombination from the survival defects with deep levels at E_C ? 0.24?eV and E_C ? 0.44?eV during annealing.     

Si-W/Si/SiO2/Si(100)的横截面电子显微镜研究

本文用横截面电子显微镜法分析了Si-W/Si/SiO₂/Si(100)在440—1000℃退火后的晶化过程,以及各个界面的变化情况.发现Si-W合金膜中,WSi₂并未优先在表面、界面处形成晶核.当退火温度不高于700℃时,反应在合金膜内发生,表面、界面起伏和缓.退火温度高达800—1000℃时,界面、表面出现原子扩散,造成剧烈的界面起伏;表面则出现小的热沟槽,Si/SiO₂界面也出现高分辨电子显微镜才能观察到的起伏.表面、界面的原子迁移的动力来源于晶界与表面、界面张力.由于SiO₂中Si—O键很稳定,不易发生Si和O在界面处的互扩散,所以Si/SiO₂界面起伏很小. 关键词：     

Effects of implantation defects on the carrier concentration of 6H-SiC

The effects of ion irradiation defects on the carrier concentration of 6H-SiC epitaxial layer were studied by current–voltage (I–V), capacitance.-voltage (C–V) measurements, thermally stimulated capacitance and deep level transient spectroscopy. The defects were produced by irradiation with 10 MeV C⁺ at a fluence of 10¹¹ ions/cm² and subsequent thermal annealings were carried out in the temperature range 500–1700 K under N₂ flux. I–V and C–V measurements reveal the presence of a high defect concentration after irradiation and annealing at temperature lower than 1000 K. Thermally stimulated capacitance measurements show that some of the defects induce a deactivation of the nitrogen donor, while some of the generated defects, behaving as donor-like traps, contribute to increase the material free carrier concentration at temperatures above their freezing point. Deep level transient spectroscopy measurements performed in the temperature range 150–450 K show the presence of several overlapping traps after ion irradiation and annealing at 1000 K: these traps suffer a recovery and a transformation at higher temperatures. The annealing of all traps at temperatures as high as 1700 K allows one to completely restore the n-type conductivity. The defects mainly responsible of the observed change in the carrier concentration are identified. PACS 73.30.+y; 61.80.Jh; 61.82.Fk; 85.30.Hi     

The study of optical properties of amorphous thin films of mixed oxides In<Subscript>2</Subscript>O<Subscript>3</Subscript>—SnO<Subscript>2</Subscript> system,deposited by co-evaporation

A discussion of optical properties of mixed oxides In₂O₃—SnO₂ system is presented. Film thickness, substrate temperature, composition (in molar %) and annealing have a profound effect on the structure and optical properties of these films. Initially the increase in band gap with the increase of SnO₂ content in In₂O₃ is due to the increase in carrier density as a result of donor electrons from tin. The decrease in band gap above the critical Sn content is caused by the defects formed by Sn atoms, which act as carrier traps rather than electron donors. The increase in band gap with film thickness is caused by the increase in free carrier density which is generated by (i) Sn atom substitution of In atom, giving out one extra electron and (ii) oxygen vacancy acting as two electrons donor. The decrease in band gap with substrate temperature and annealing is due either to the severe deficiency of oxygen, which deteriorate the film properties and reduce the mobility of the carriers, or to the formation of indium species of lower oxidation state (In²⁺).     

Hydrostatic pressure effects on oxygen-related irradiation-produced defects in silicon

Abstract

Hydrostatic pressure has been used as a variable to investigate the E_c-0.164 eV acceptor level for the oxygen-vacancy (O—V) defect in γ-ray irradiated Si, and the annealing/formation of oxygen-related defects in neutron-irradiated Si. The acceptor level is found by deep level transient spectroscopy to move closer to the conduction band and away from the valence band at rates of 3.9 meV/kbar and 2.4 meV/kbar, respectively, i.e., the level moves higher in the gap. There is also a relatively large inward (outward) breathing mode lattice relaxation (4.6±1.2 ų/electron) accompanying electron emission (capture) from this level. Both results reflect the antibonding nature of the level and are qualitatively consistent with the Watkins—Corbett model for the O—V defect. The annealing rate was found by infrared absorption to increase with pressure for the O—V defect at 350°C with a derived activation volume of ?4.5 ų/defect, where the negative sign implies inward relaxation (contraction) on annealing. Pressure has relatively little effect on annealing of the C—Si—O C(3) defect which is interstitial in nature, but strongly favors the formation of the dioxygen (2 oxygen atoms per vacancy, i.e., O₂—V) defect. The intensity of the O₂—V band after annealing at 20 kbar is 5 times higher than that following similar annealing at 0 kbar. Additionally, this intensity at 20 kbar is higher than that achievable by any isochronal or isothermal annealing steps at 0 kbar. These annealing/formation results are discussed qualitatively in terms of models for the various defects.     

Influence of annealing at temperatures above the solidus temperature on the structure and galvanomagnetic properties of Bi<Subscript>92</Subscript>Sb<Subscript>8</Subscript> solid-solution thin films

The influence of the annealing temperature from the interval between the solidus and liquidus temperatures of Bi₉₂Sb₈ solid solution on its structure and galvanomagnetic and thermoelectric properties has been studied. It has been shown that films of bismuth–antimony solid solution grown by thermal evaporation in a vacuum will have a large-grained structure after annealing at temperatures higher than the solidus temperature of the solid solution. It has been found that these films offer the lowest resistivity, the highest relative magnetoresistance, and the highest mobility of charge carriers. As the annealing temperature approaches the liquidus temperature, the probability that a dendritic structure will form and antimony-enriched regions will appear grows. This causes an increase in the charge carrier concentration and a decrease in the resistivity with a decrease in the relative magnetoresistance and charge carrier mobility.     

高温电子辐照硅中缺陷的研究

本文对高温电子辐照硅中产生的缺陷进行了研究,发现缺陷的引进率随电子辐照温度的增加而增加,在达到极值温度T_m后,缺陷的引进率将随之而下降,T_m值与缺陷的退火激活能有关。E₃缺陷(E_c—0.36eV)浓度在高温电子辐照中显著增加,在330℃高温电子辐照时,E₃缺陷浓度为室温电子辐照的6倍。研究结果表明,E₃缺陷的可能结构为与多空位和氧有关的复合体。 关键词：     

Co掺杂纳米ZnO微结构的正电子湮没研究

利用正电子湮没技术研究了10 at.% Co掺杂的Co₃O₄/ZnO纳米复合物中退火对缺陷的影响. 利用X射线衍射(XRD)测量了Co₃O₄/ZnO纳米复合物的结构和晶粒尺寸. 随着退火温度升高,Co₃O₄相逐步消失,ZnO晶粒尺寸也有显著增加. 经过1000 ℃以上退火后,Co₃O₄相完全消失,并出现了CoO的岩盐结构. 正电子湮没寿命测量显示出Co₃O₄ /ZnO纳米复合物中存在大量的Zn空位和空位团. 这些空位缺陷可能存在于纳米复合物的界面区域. 当退火温度达到700 ℃后Zn空位开始恢复,空位团也开始收缩. 900 ℃以上退火后,所有空位缺陷基本消失,正电子寿命接近ZnO完整晶格中的体态寿命值. 符合多普勒展宽谱测量也显示Co₃O₄ /ZnO纳米复合物经过900 ℃以上退火后电子动量分布与单晶ZnO基本一致,表明界面缺陷经过退火后得到消除. 关键词： ZnO 界面缺陷 正电子湮没     

Improvement of transport properties for polycrystalline silicon prepared by plasma-enhanced chemical vapor deposition

The carrier transport property of polycrystalline silicon (poly-Si:H:F) thin films was studied in relation to film microstructure, impurity, in situ or post-annealing treatments to obtain better carrier transport properties. Poly-Si:H:F films were prepared from SiF₄ and H₂ gas mixtures at temperatures <300 °C. Dark conductivity of the films prepared at high SiF₄/H₂ gas flow ratio (e.g., 60/3 sccm) exhibits a high value for intrinsic silicon and its Fermi level is located near the conduction band edge. The carrier incorporation is suppressed well, either by in situ hydrogen plasma treatment or by post-annealing with high-pressure hot-H₂O vapor. It is confirmed that weak-bonded hydrogen atoms are removed by the hot-H₂O vapor annealing. In addition, evident correlation between impurity concentrations and dark conductivity is not found for these films. It is thought that the carrier incorporation in the films prepared at high SiF₄/H₂ gas flow ratios is related to grain-boundary defects such as weak-bonded hydrogen. By applying hot-H₂O vapor annealing at 310 °C to a 1-μm-thick p-doped (400)-oriented poly-Si:H:F film, Hall mobility was improved from 10 cm²/Vs to 17 cm²/Vs. Received: 7 August 2000 / Accepted: 2 March 2001 / Published online: 20 June 2001     

真空热退火温度对单相Ag2O薄膜微结构和光学性质的影响

利用直流磁控反应溅射技术在玻璃衬底上沉积了单相Ag₂O薄膜,并采用真空热退火对单相Ag₂O薄膜在不同热退火温度 (T _{A) 下进行了1 h热处理.利用X射线衍射谱、扫描电子显微镜和分光光度计研究了 T A对单相Ag2O薄膜微结构和光学性质的影响.研究结果表明, T}A= 300 ℃ 时Ag₂O薄膜中开始出现Ag纳米颗粒,且随着 T _{A的升高薄膜中Ag的含量 关键词： 2}O薄膜')" href="#">Ag₂O薄膜 热退火温度 微结构 光学性质