用掺杂液晶制作光电池

丹麦工艺学院研制出一种新型掺杂液晶光电池,它的结构和液晶显示器相似.它有两块1×4(厘米)的石英板,石英板边缘用聚酯薄膜隔开,间距为25微米,中间注入含有10%咔唑(从煤中提炼出的一种光敏低分子化合物)的向列正温型液晶材料;电极是小于1微米厚的铟-锡-氧化物层,通过涂银铜线与外界相接.     

激光诱导化学气相沉积纳米硅的红外光谱

对激光化学气相沉积纳米硅的红外光谱进行了研究，结合红外光声光谱考察了退火处理对其红外光谱吸收峰位置的影响，对纳米硅的红外吸收峰进行了标识和讨论。     

激光诱导化学气相沉积纳米硅的红外光谱

对激光化学气相沉积纳米硅的红外光谱进行了研究，结合红外光场光谱考察了退火处理对其红外光谱吸收峰位置的影响，对纳米硅的红外吸收峰进行了标识和讨论。     

激光化学气相沉积无定形硅

用激光化学气相沉积方法得到了无定形硅薄膜。用干涉仪测得薄膜厚度为微米量级,沉积速率为100(?)/min,用扫描电镜测出无定形硅颗粒平均线度为40～50(?),用激光拉曼光谱仪测出其拉曼频移为480cm~(-1)实验得到了沉积速率随气体峰值温度变化曲线,认为沉积速率受限步骤是硅烷的气相反应,求出反应活化能为192.6kJ/mol。     

激光化学气相沉积无定形硅的研究

用激光化学气相沉积方法在微晶玻璃基片上沉积出了无定形硅薄膜。用乌氏干涉仪测得薄膜厚度为微米量级,沉积速率为100埃/分;用扫描电镜拍摄了膜层的形貌照片,测得其线度为40～50埃;用喇曼光谱仪测出其喇曼频移为480cm~(-1),与无定形硅的特征喇曼频移一致。     

基于硅光电池的激光监听器

随着反监听技术的发展,传统的接触式、有源式监听器逐渐暴露出安装困难、容易留下痕迹等缺点,激光监听器因其非接触性、隐蔽性、抗干扰能力强等优点逐步成为各国研究和发展的对象。激光监听技术以激光作为传感介质,对容易受音频信号激励的振动物体照射,提取并分析其回射信号中携带的振动调制信息,通过信号处理技术即可还原音频信号。该文介绍了激光监听的原理,并设计了采用硅光电池作为探测器的激光监听系统,在实验室进行测试,取得了良好的效果。     

硅光电池的激光损伤机制

研究了激光对硅光电池的损伤，实验表明，损伤前后的饱和开路电压相等，损伤程度取决于损伤面积，损伤后伏安曲线变得平直，说明文献［１］提出的锑化钢光伏型探测器激光损伤的并联电阻模型有普遍意义。实验还发现激光损伤将导致反向击穿电压降低。     

激光诱导硅烷气相合成纳米硅粉研究

采用高功率ＣＯ２激光诱导高纯硅烷气相反应，制备出粉体平均粒径为１０～１２０ｕｍ，晶粒度与平均粒径比为０．３～０．７的各种纳米结晶硅粉。制备出的硅粉粒度均匀，粒子呈球形，但部分粒子间出现烧结。粉体粒径随激光功率、反应压力的增加而增加，随硅烷流量、稀释Ａｒ气的增加而减小。晶粒度对硅烷流量和反应压力的变化不敏感，但随激光功率的降低和混合Ａｒ气的增加而明显减小。Ｓｉ粒子的形成经历了单晶粒子的生长和这些粒子间的碰撞生长过程。     

飞秒激光与准分子激光制作碲掺杂硅探测器

采用飞秒激光扫描P型单晶硅衬底上的碲单质膜层,实现了碲元素在硅中的N型掺杂,随后利用准分子激光对掺杂样品进行退火处理,制备了碲掺杂硅单晶材料。利用该材料研制出了在室温下具有高响应的碲掺杂硅探测器。在-4V的反向偏压下,光电响应在1000nm处达到0.86A/W,外量子效率大于106.6%;随着反向偏压的增加,光电响应增加,同时截止波长向红外方向拓展,在-8V偏压下,截止波长达到了1235nm;在-16V偏压下,测得响应在1080nm处最高达到3.27A/W。     

激光诱导化学掺杂及其在半导体器件制备中的应用

本文在叙述了激光诱导化学掺杂技术基本原理的基础上,主要介绍了连续波激光直写化学掺杂和脉冲激光化学掺杂的方法及其掺杂特性,最后简要介绍了它在半导体器件制备工艺中的应用。     

Microwave annealing for ultra-shallow junction formation

We propose a new method for activation of source/drain junctions by microwave annealing. A study with B/BF₂ implants at ultralow energies (300/500 eV) and high doses (1E15/5E15 cm⁻²) was completed. The samples were subjected to a high-power cyclotron resonance maser, called a “gyrotron,” for annealing. There appears to be some evidence of electromagnetic field-aided activation. The activation levels achieved exceed the levels reported by thermal means at the corresponding temperatures. Secondary ion mass spectroscopy (SIMS) was used to examine the impurity profile after ion implantation and diffusion. Spreading resistance profiling was used to examine the activated dopant profile.     

n/p ultra-shallow junction formation with plasma immersion ion implantation

n⁺/p ultra-shallow junctions formed by PH₃ plasma immersion ion implantation (PIII) have been studied and diodes with good electrical characteristics have been obtained. The influence of annealing conditions and carrier gas on junction depth and sheet resistance have been studied. It is found that a higher content of H and/or He in silicon can slow down the diffusion of phosphorus and the activation ability of implanted dopant ions in silicon; a shallower junction can been obtained with He rather than H₂ as the carrier gas; and the influence of annealing at 850°C for 20 s on sheet resistance is opposite to that of annealing at 900°C for 6 s on sheet resistance. In addition, mechanisms of unusual electrical characteristics for some diodes are discussed and analyzed in this paper.     

Characterization of ultra-shallow p+-n junction diodesfabricated by 500-eV boron-ion implantation

Ultrashallow gated diodes have been fabricated using 500-eV boron-ion implantation into both Ge-preamorphized and crystalline silicon substrates. Junction depths following rapid thermal annealing (RTA) for 10 s at either 950°C or 1050°C were determined to be 60 and 80 nm, respectively. These are reportedly the shallowest junctions formed via ion implantation. Consideration of several parameters, e.g. reduced B⁺ channeling, increased activation, and reduced junction leakage current, lead to the selection of 15 keV as the optimal Ge preamorphization energy. Transmission electron microscope results indicated that an 850°C/10-s RTA was sufficient to remove the majority of bulk defects resulting from the Ge implant. Resulting reverse leakage currents were as low as 1 nA/cm² for the 60-nm junctions and diode ideality factors for crystalline and preamorphized substrates ranged from 1.02 to 1.12. Even at RTA temperatures as low as 850°C, the leakage current was only 11 nA/cm ². The final junction depths were found to be approximately the same for both preamorphized and nonpreamorphized samples after annealing at 950°C and 1050°C. However, the preamorphized sample exhibited significantly improved dopant activation     

The influence of Ge-implantation on the electrical characteristicsof the ultra-shallow junction formed by using silicide as a diffusionsource

The electrical characteristics of ultra-shallow p⁺/n junctions formed by implanting a 60 keV Ge⁺ into a TiSi₂ layer have been studied. A very low reverse leakage current density (≅0.4 nA/cm² at -5 V) and a very good forward ideality factor n (≅1.001) were achieved in these ultra-shallow p ⁺/n junctions. From the secondary ion mass spectrometry (SIMS) analysis, the junction depth was measured to be 600 Å and the surface concentration was about 3 times higher than that of the conventional samples     

Device-grade ultra-shallow junctions fabricated with antimony

Extremely shallow, below ∼80 nm, n+ junctions fabricated with antimony have been analytically and electrically investigated. It is shown that by the use of antimony one can reach sheet resistivity/ shallowness combinations that are superior to those achievable with arsenic. The leakage of these junctions was found to be sufficiently low to allow VLSI applications. These investigations indicate that below a certain junction depth antimony should be the dopant of preference.     

P-MOSFET's with ultra-shallow solid-phase-diffused drain structureproduced by diffusion from BSG gate-sidewall

A p-MOSFET structure with solid-phase diffused drain (SPDD) is proposed for future 0.1-μm and sub-0.1-μm devices. Highly doped ultrashallow p⁺ source and drain junctions have been obtained by solid-phase diffusion from a highly doped borosilicate glass (BSG) sidewall. The resulting shallow, high-concentration drain profile significantly improves short channel effects without increasing parasitic resistance. At the same time, an in situ highly-boron-doped LPCVD polysilicon gate is introduced to prevent the transconductance degradation which arises in ultrasmall p-MOSFETs with lower process temperature as a result of depletion formation in the p⁺-polysilicon gate. Excellent electrical characteristics and good hot-carrier reliability are achieved     

Effects of AsH3 surface treatment for the improvement of ultra-shallow area-selective regrown GaAs sidewall tunnel junction

Low-temperature (290°C) area-selective regrowth by molecular layer epitaxy (MLE) was applied for the fabrication of an ultra-shallow sidewall (50 nm) GaAs tunnel junction. Fabricated tunnel junctions have shown a record peak current density up to 35,000 A/cm². It is shown that the tunnel junction characteristics are strongly dependent on the sidewall orientation and the AsH₃ surface treatment conditions just prior to regrowth. The effects of AsH₃ surface treatment are discussed in view of the control of surface stoichiometry.     

A proposed planar junction structure with near-ideal breakdown characteristics

Addition of a low-concentration p-type pocket around the edge region of p⁺-n type planar junction improves the electric-field distribution to such an extent that near-ideal breakdown characteristics can be obtained. This has been observed in 2-dimensional computer simulation studies. This is based on the fact that for a specific combination of width and depth of the pocket, the region in which maximum avalanche multiplication occurs, changes from the edge to the plane. Worst-case analysis taking constant impurity profiles in all the regions and rectangular junctions has been presented to know the influence of the edge region. The present structure, if realized by the methods indicated, would result in the highest breakdown voltage of a planar junction     

新型双波长激光器热学特性研究

制备了一种新型双波长和单波长隧道再生半导体激光器,测试了两种激光器在25~105℃温度范围内的P-I特性曲线,对比分析了两种激光器输出光功率、阈值电流、斜率效率随温度的变化。测试结果表明,新型双波长隧道再生激光器有高输出功率、高斜率效率以及双激射波长等优点;高掺杂隧道结的引入以及双有源区的器件结构导致其热特性略差于单波长半导体激光器。     

Effect of number of laser pulses on p+/n silicon ultra-shallow junction formation during non-melt ultra-violet laser thermal annealing

We investigate the effect of the number of laser pulses on the formation of p⁺/n silicon ultra-shallow junctions during non-melt ultra-violet laser (wavelength, 355 nm) annealing. Through surface peak temperature calculating by COMSOL Multiphysics, the non-melt laser thermal annealing is performed under the energy density of 130 mJ/cm². We demonstrate that increasing the number of laser pulses without additional pre-annealing is an effective annealing method for achieving good electrical properties and shallow junction depth by analyzing sheet resistance and junction depth profiles. The optimal number of laser pulses is eight for achieving a high degree of activation of dopant without further increase of junction depth. We have also explained the improved electrical characteristics of the samples on the basis of fully recovered crystallinity as revealed by Raman spectroscopy. Thus, it is suggested that controlling the number of laser pulses with moderate energy density is a promising laser annealing method without additional pre-annealing.