BF_2~+注入多晶硅栅的SIMS分析

文本采用SIMS技术,分析了BF_2~+注入多晶硅栅退火前后F原子在多晶硅和SiO_2中的迁移特性。结果表明,80keV,2×10~(15)和5×10~(15)cm~(-2) BF_2~+注入多晶硅栅经过900℃,30min退火后,部分F原子已扩散到SiO_a中。F在多晶硅和SiO_2中的迁移行为呈现不规则的特性,这归因于损伤缺陷和键缺陷对F原子的富集作用。     

BF2^＋注入多晶硅栅的SIMS分析

文本采用ＳＩＭＳ技术，分析了ＢＦ２＾＋注入多晶硅栅退火前后Ｆ原子在多晶硅和ＳｉＯ２中的迁移特性，结果表明，８０ｋｅＶ，２×１０＾１５和５×１０＾１５ｃｍ＾－２ＢＦ２＾＋注入多晶硅栅经过９００℃，ｍｉｎ退火后，部分Ｆ原子已扩散到ＳｉＯ２中，Ｆ在多晶硅和ＳｉＯ２中的迁移行为呈现不规则的特性，这归因于损伤缺陷和键缺陷对Ｆ原子的富集作用。     

双色红外焦平面研究进展

介绍了叠层双色红外焦平面的发展背景和适用的材料体系,及其在国际上的发展现状,重点论述了叠层双色探测器结构类型及其探测特点,最后介绍了国内碲镉汞叠层双色焦平面的研究进展。报道了基于n⁺_-p-P-P-N多层异质结Hg_1-xCd_xTe材料的叠层中波/短波（256×1）×2红外双色焦平面器件研制及性能。在77 K液氮温度下,红外焦平面探测器的两个波段的截止波长λ_c分别为2.8 μm和3.9 μm,中波/短波焦平面的平均单色探测率D*_λp分别为1.8×10¹¹ cmHz^1/2/W和9.6×10¹⁰ cmHz^1/2/W。     

BF+2注入的多晶硅薄膜快速热退火后氟行为的研究

本文报道BF_2~+注入的多晶硅薄膜经快速热退火后的物理和电学性质。发现造成氟异常分布的原因是由于快速热退火过程中氟的外扩散以及在多晶硅/二氧化硅界面处的聚集。在注入剂量为1×10~(15)和5×10~(15)cm~(-2)的样品中,经快速热退火后可以观察到氟泡。     

快速退火BF+注入非晶硅薄膜的显微分析

BF⁺ with 92keV and 1×10¹⁵/cm² was implanted into a-Si∶H film prepar ed by PECVD,then implanted sample has been rapid annealed using CWCO₂ Laser wi th output of 60W and spot size 0.2cm in diameter at 10s time.Microscopic topogr aphies analysis with SEM indicate thatUnder our annealing condition,the profile s of multi-structure defects in a-Si∶H film produced by BF⁺ implanting are some shapes of rectangle-like and square-like.Crystallization started from the edges of multi-structure defects.Crystallized procedure and the mechanism have been discussed.     

环F2+uF2+…+uk-1F2上长为2S的(1+u)-常循环码的距离分布

研究码字的距离分布是编码理论的一个重要研究方向。该文定义了环R=F₂+uF₂+…+u^k-1F₂上的Homogeneous重量,研究了环R上长为2^S的(1+u)-常循环码的Hamming距离和Homogeneous距离。使用了有限环和域的理论,给出了环R上长为2^S的(1+u)-常循环码和循环自对偶码的结构和码字个数。并利用该常循环码的结构,确定了环R上长为2^S的(1+u)-常循环码的Hamming距离和Homogeneous距离分布。     

BF_2~+注入单晶硅和多晶硅栅快速热退火氟迁移特性的SIMS分析

本文借助ＳＩＭＳ技术，系统地分析了４５ｋｅＶ，１×１０１４、２×１０１５和５×１０１５ｃｍ－２ＢＦ＋２注入单晶硅和８０ｋｅＶ、２×１０１５ｃｍ－２ＢＦ＋２注入多晶硅栅在快速退火条件下，Ｆ在单晶硅和多晶硅栅中的分布剖面，并对Ｆ在单晶硅和多晶硅栅中的迁移特性进行了深入的分析和讨论．Ｆ在多晶硅栅中的迁移，不但存在着Ｆ的扩散，而且还存在着Ｆ的发射和吸收，据此成功地解释了实验结果．     

开槽耦合型H01οH0nο模式变换器

本文叙述了一种新型的开槽耦合型H₀₁^οH_0n^ο 模式变换器的设计原理、制作技术以及在8mm波段的实测结果。它显示了宽带特性。在32-37GHz的频带内,输入驻波比低于1.1;变换损耗低于1dB;杂模H₀₁^ο幅度低于－15dB。     

高k HfLaO栅介质MoS2晶体管的性能研究

比较研究了HfO₂与HfLaO栅介质多层MoS₂场效应晶体管。实验结果表明,与HfO₂栅介质MoS₂晶体管相比,HfLaO栅介质MoS₂晶体管表现出更优的电性能。电流开关比高达1×10⁸,亚阈斜率低至76 mV/dec,界面态密度低至1.1×10¹² cm-2·eV-1,载流子场效应迁移率高达1×10⁹ cm²·V-1·s-1。性能改善的原因在于镧(La)对HfO₂的掺杂形成HfLaO化合物,减小栅介质薄膜的表面粗糙度,降低缺陷电荷密度,改善了栅介质/沟道界面特性,从而减小了界面态密度,抑制了库仑散射和界面粗糙散射。最终,提高了多层MoS₂晶体管的场效应迁移率,改善了晶体管的亚阈特性。     

TiO2陶瓷晶界层电容器的研究

本文对TiO₂陶瓷晶界层电容器进行了较为系统的研究。用液相喷雾干燥法制备含Nb⁵⁺,Ba²⁺微量杂质的TiO₂超细原料粉末,研究了TiO₂陶瓷的电性能与烧结温度和测试条件的关系,阐述了TiO₂晶界层电容器的形成机制。     

Comparison of p–n junction formed by BF2 and B implantation in silicon microstrip detector with low and high thermal budget: impact of fluorine on electrical characteristics

The influence of crystal damage on the electrical properties and the doping profile of the implanted p⁺–n junction has been studied at different annealing temperatures using process simulator TMA-SUPREM4. This was done by carrying out two different implantations; one with implantation dose of 10¹⁵ BF₂⁺ ions/cm² at an energy of 80 keV and other with 10¹⁵ B⁺ ions/cm² at 17.93 keV. Substrate orientation 1 1 1 of phosphorus-doped n-type Si wafers of resistivity 4 kΩ cm and tilt 7° was used, and isochronally annealing was performed in N₂ ambient for 180 min in temperature range between 400°C and 1350°C. The diode properties were analysed in terms of junction depth, sheet resistance. It has been found that for low thermal budget annealing, boron diffusion depth is insensitive to the variation in annealing temperature for BF₂⁺-implanted devices, whereas, boron diffusion depth increases continuously for B⁺-implanted devices. In BF₂⁺-implanted devices, fluorine diffusion improves the breakdown voltage of the silicon microstrip detector for annealing temperature upto 900°C.For high thermal budget annealing, it has been shown that the electrical characteristics of BF₂⁺-implanted devices is similar to that obtained in B⁺-implanted devices.     

Diffusion of ion-implanted boron impurities into pre-amorphized silicon

Boron ion implantation into pre-amorphized silicon is studied. Pre-amorphization is performed either by F⁺ or Si⁺ implantation prior to B⁺ implantation at 10 keV with 3×10¹⁵ ions/cm². Broadening of the boron profile can be suppressed markedly in the pre-amorphized layers. For instance, the as-implanted depth at a B concentration of 1×10¹⁸ atoms/cm³ decreases from 0.19 to 0.1 μm for implantation into a pre-amorphized layer compared to B implantation into crystalline silicon. After annealing at 950°C, B atoms diffuse much more rapidly in the pre-amorphized layers than in the crystalline silicon case. Nevertheless, shallower junctions are obtained with the use of pre-amorphization. For dual F⁺ and B⁺ implantation at F⁺ doses above 1×10¹⁵ F⁺/cm², fluorine is found to segregate to the peak of the boron profile during annealing. Fluorine is also trapped at the peak of the as-implanted fluorine profile peak and near the amorphous–crystalline interface. The effects of fluorine dose and anneal temperature on the F precipitation are described and compared to results for BF⁺₂ implants.     

砷化镓汽相外延中Cd的行为和p-n结材料的制备

一、引言 在CaAs气相外延中,除了用各种掺杂剂制得n型材料外,也有少量工作述及P型外延层的制备。鉴于P型材料可用作双漂移二极管和太阳能电池,本文在GaAsCl_3-H_2体系中采用元素Cd为掺杂剂,研究了Cd的掺杂行为并制得了各种结构的p-n材料。 二、实验 实验装置与文献[2]基本相似。H_2分三路进入反应管,即主路,旁路和掺杂路;AsCl_3为主、旁两路,主路用于生长外延层,旁路用作掺杂和原位气相腐蚀。 掺杂源为元素Cd,置于磁拉舟内,不掺杂时放任冷处,掺杂时拉入给定的温区,以获得一定的Cd浓度。     

确定BBOS对称序列左右界顶点子集的一个通项公式

根据本文作者之一(1991)提出的S_BOS相邻逻辑对称序列的性质,给出确定S_BOS对称序列左右界两顶点子集的一个通项公式。这对于利用“对跳定界搜索”法快速实现S_BOS对称序列,提供了一个选择定界范围和实用算法的依据。     

Effect of O+ implantation on silicon-silicon dioxide interface properties

A detailed investigation has been made by the MOS capacitance method, into the mechanism by which the fixed positive surface state charge, due to silicon rich oxide near SiSiO₂ interface, is controlled by O⁺ implantation into the oxide near the SiSiO₂ interface, and subsequent heat treatment. High dosage implantation of 3 × 10¹³ O⁺ ions cm^?2 results in damage in oxide which is occured by 450°C annealing. However, low dosage implantation of 3 × 10^?2 produces no detectable damage in the oxide, and increases the effective positive charge in the oxide at Si'SiO₂ interface. It is shown that prolonged 450°C heat treatment of 0⁺ ion implanted oxides results in an oxygen-silicon reaction in the silicon enriched oxide layer and reduces the fixed positive surface state charge. Subsequent heat treatments at 838°C increase the positive surface state charge to the original pre-ion implantation values, hence converting the oxide into the original silicon rich condition.     

Fluorine behavior in BF 2 + implanted polysilicon films subjected to rapid thermal annealing

The physical and electrical properties of BF ₂ ⁺ implanted polysilicon films subjected to rapid thermal annealing (RTA) are presented. It is found that the out diffusion ofF and its segregation at polysilicon/silicon oxide interface during RTA are the major causes ofF anomalous migration. Fluorine bubbles were observed in BF ₂ ⁺ implanted samples at doses of 1×10¹⁵ and 5×10¹⁵ cm⁻² after RTA.     

Diffusion-Controlled growth of Ge nanocrystals in SiO<Subscript>2</Subscript> films under conditions of ion synthesis at high pressure

The growth of Ge nanocrystals in SiO₂ films is studied in relation to the dose of implanted Ge⁺ ions and the annealing temperature at a pressure of 12 kbar. It is established that the dependences of the nanocrystal dimensions on the content of Ge atoms and the annealing time are described by the corresponding root functions. The nanocrystal radius squared is an exponential function of the inverse temperature. The dependences correspond to the model of the diffusion-controlled mechanism of nanocrystal growth. From the temperature dependence of the nanocrystal dimensions, the diffusion coefficient of Ge in SiO₂ at a pressure of 12 kbar is determined: D = 1.1 × 10^–10 exp(–1.43/kT). An increase in the diffusion coefficient of Ge under pressure is attributed to the change in the activation volume of the formation and migration of point defects. Evidence in favor of the interstitial mechanism of the diffusion of Ge atoms to nanocrystal nuclei in SiO₂ is reported.     

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.