具有复合埋层的新型SIMON材料的制备

采用氮氧共注入方法制备了新型的SIMON(separation by implanted oxygen and nitrogen)SOI材料.采用不同的制备方法分别制作出样品并进行了结构测试和分析,发现SIMON材料的结构和质量对注入条件和退火工艺非常敏感.并对各种氮氧复合注入技术做了分析和比较,发现氮氧分次注入可以得到更好的结构和性能.     

注氮工艺对SOI材料抗辐照性能的影响

分别采用一步和分步注入的工艺制备了氧氮共注形成SOI(SIMON)材料,并对退火后的材料进行了二次离子质谱(SIMS)分析,结果发现退火之后氮原子大多数聚集在SiO2/Si界面处.为了分析材料的抗辐照加固效果,分别在不同方法制作的SIMON材料上制作了nMOS场效应晶体管,并测试了晶体管辐射前后的转移特性.实验结果表明,注氮工艺对SOI材料的抗辐照性能有显著的影响.     

注氮工艺对SOI材料抗辐照性能的影响

分别采用一步和分步注入的工艺制备了氧氮共注形成SOI(SIMON)材料，并对退火后的材料进行了二次离子质谱（SIMS）分析，结果发现退火之后氮原子大多数聚集在SiO2/Si界面处．为了分析材料的抗辐照加固效果，分别在不同方法制作的SIMON材料上制作了nMOS场效应晶体管，并测试了晶体管辐射前后的转移特性．实验结果表明，注氮工艺对SOI材料的抗辐照性能有显著的影响．     

应用ICP-AES表征高剂量氧注入过程中的金属污染

研究了采用感应耦合等离子体原子发射光谱技术表征高剂量氧注入单晶硅制备SIMOX SOI材料过程中金属杂质污染的有效性.同时研究了采用强酸清洗、加SiO2 膜覆盖等方法对降低污染程度的效果.利用ICP技术可以对大面积或整个硅片进行采样,检测结果是一种整体的平均效果.采用强流氧注入机进行高剂量氧注入,发现金属杂质污染元素主要是Al、Ar、Fe、Ni;注入后强酸清洗样品可有效降低Al污染;6 0nm厚的二氧化硅注入保护膜可阻挡一半的上述金属污染.     

应用ICP-AES表征高剂量氧注入过程中的金属污染

研究了采用感应耦合等离子体-原子发射光谱技术表征高剂量氧注入单晶硅制备SIMOX-SOI材料过程中金属杂质污染的有效性.同时研究了采用强酸清洗、加SiO2膜覆盖等方法对降低污染程度的效果.利用ICP技术可以对大面积或整个硅片进行采样,检测结果是一种整体的平均效果.采用强流氧注入机进行高剂量氧注入,发现金属杂质污染元素主要是Al、Ar、Fe、Ni;注入后强酸清洗样品可有效降低Al污染;60nm厚的二氧化硅注入保护膜可阻挡一半的上述金属污染.     

SIMOX埋氧层的总剂量辐射硬度对埋氧层中注氮剂量的敏感性

为了提高SIMOX(separation-by-implanted-oxygen)SOI(silicon-on-insulator)结构中埋氧层(BOX)的总剂量辐射硬度,埋氧层中分别注入了2×1015和3×1015cm-2剂量的氮.实验结果表明,在使用Co-60源对埋氧层进行较低总剂量的辐照时,埋氧层的总剂量辐射硬度对注氮剂量是非常敏感的.尽管埋氧层中注氮剂量的差别很小,但经5×104 rad(Si)剂量的辐照后,注入2×1015cm-2剂量氮的埋氧层表现出了比未注氮埋氧层高得多的辐射硬度,而注入3×1015cm-2剂量氮的埋氧层的辐射硬度却比未注氮埋氧层的辐射硬度还低.然而,随辐照剂量的增加(从5×104到5×105rad(Si)),这种埋氧层的总剂量辐射硬度对注氮剂量的敏感性降低了.采用去掉SOI顶硅层的MOS高频C-V技术来表征埋氧层的总剂量辐射硬度.另外,观察到了MSOS(metal-silicon-BOX-silicon)结构的异常高频C-V曲线,并对其进行了解释.     

GD非晶硅中氧、氮对其光电特性的影响

研究了以氧、氮或它们的混合气体作为掺杂材料所制备的a-Si 薄膜,并分析了掺杂后对其光电特性的影响.在我们的实验室中,不掺杂的样品是高阻和低光电导的,然而在GD制备过程中引入适量的氧或氮,可使其暗电导和光电导发生很大变化,在合适的条件下,其典型值可分别增加七个和四个数量级.文中给出了暗电导、光电导与掺杂量的关系;不同掺杂材料的电导激活能;红外吸收谱和隙态密度分布曲线等.文章最后对结果作了推测性的讨论.并认为,在GD法制备非晶硅薄膜过程中,微量的氧和氮是导致材料光电特性分散的一个重要因素.     

Sensitivity of Total-Dose Radiation Hardness of SIMOX Buried Oxides to Doses of Nitrogen Implantation into Buried Oxides

为了提高SIMOX(separation-by-implanted-oxygen)SOI(silicon-on-insulator)结构中埋氧层(BOX)的总剂量辐射硬度,埋氧层中分别注入了2×1015和3×1015cm-2剂量的氮.实验结果表明,在使用Co-60源对埋氧层进行较低总剂量的辐照时,埋氧层的总剂量辐射硬度对注氮剂量是非常敏感的.尽管埋氧层中注氮剂量的差别很小,但经5×104 rad(Si)剂量的辐照后,注入2×1015cm-2剂量氮的埋氧层表现出了比未注氮埋氧层高得多的辐射硬度,而注入3×1015cm-2剂量氮的埋氧层的辐射硬度却比未注氮埋氧层的辐射硬度还低.然而,随辐照剂量的增加(从5×104到5×105rad(Si)),这种埋氧层的总剂量辐射硬度对注氮剂量的敏感性降低了.采用去掉SOI顶硅层的MOS高频C-V技术来表征埋氧层的总剂量辐射硬度.另外,观察到了MSOS(metal-silicon-BOX-silicon)结构的异常高频C-V曲线,并对其进行了解释.     

注氮剂量对SOI材料埋氧中电荷密度的影响

为对SIMOX SOI材料进行抗总剂量辐照加固,可向材料的埋氧（BOX）层中注入一定剂量的氮元素。但是,研究发现,注氮埋层中的初始电荷密度皆为正值且密度较高,而且随着注氮剂量的增加而上升。注氮埋层中较高的正电荷密度可归因于氮在退火过程中在Si-BOX界面的积累。另外,与注氮埋层不同的是,注氟的埋层却显示出具有负的电荷密度。为得到埋层的电荷密度,测试用样品制成金属-埋氧-半导体(MBS)电容结构,用于进行高频C-V测量分析。     

SIMON64算法的积分分析

SIMON系列算法自提出以来便受到了广泛关注。积分分析方面,Wang,Fu和Chu等人给出了SIMON32和SIMON48算法的积分分析,该文在已有的分析结果上,进一步考虑了更长分组的SIMON64算法的积分分析。基于Xiang等人找到的18轮积分区分器,该文先利用中间相遇技术和部分和技术给出了25轮SIMON64/128算法的积分分析,接着利用等价密钥技术进一步降低了攻击过程中需要猜测的密钥量,并给出了26轮SIMON64/128算法的积分分析。通过进一步的分析,该文发现高版本的SIMON算法具有更好抵抗积分分析的能力。     

硅离子注入对全耗尽SIMOX材料总剂量效应的影响

Total dose hardened fully-depleted SOI materials are fabricated on separation by implanted oxygen （SIMOX） materials by silicon ion implantation and annealing. The ID-VG characteristics of pseudo-MOS transistors pre- and post-irradiation are tested with ^60Co gamma rays. The chemical bonds and the structure of Si in the buried oxide are also studied by X-ray photoelectron spectroscopy and cross-sectional high-resolution transmission electron microscopy, respectively. The results show that Si nanocrystals in the buried oxide produced by ion implantation are efficient deep electron traps, which can significantly compensate positive charge buildup during irradiation. Si implantation can enhance the total-dose radiation tolerance of the fully-depleted SOI materials.     

The characteristics of CMOS devices in oxygen-implantedsilicon-on-insulator structures

The characteristics of CMOS devices fabricated in oxygen-implanted silicon-on-insulator (SOI) substrates with different oxygen doses are studied. The results show that transistor junction leakage currents are improved by orders of magnitude when the oxygen dose is decreased from 2.25×10¹⁸ cm^-2 to 1.4×10¹⁸ cm^-2 . The floating-body effect, i.e. transistor turn-on at lower gate voltage with dramatic improvement in subthreshold slope when the drain voltage is increased, is enhanced by the reduction in leakage current and hence the oxygen dose. In SOI substrates implanted with 1.4×10¹⁷ cm^-2 oxygen dose and annealed at 1150°C, back-channel mobilities are decreased by several orders of magnitude compared to the mobilities in the precipitate-free silicon film. These device characteristics are correlated with the microstructure at the silicon-buried-oxide interface, which is controlled by oxygen implantation and post-oxygen-implantation anneal     

An advanced Ge preamorphization salicide technology forultra-thin-film SOI CMOS devices

In this letter, we propose a new approach to implement salicide on thin-film silicon-on-insulator (SOI) through the amorphization of the source/drain (S/D) regions by a germanium implantation. The amorphous film greatly reduces the silicide formation energy and effectively controls the silicide depth. This results in a much lower thermal cycle and increased flexibility in the choice of metal thickness. SOI NMOS devices fabricated using this novel salicide technology have shown substantially reduced S/D resistance as well as good device performance. This technology is applicable to PMOS SOI MOSFETs as well     

退火温度对SOI材料与器件性能的影响

在注氧形成的SOI衬底上制作了P型MOSFET。本文研究了不同退火温度对材料形成与器件性能的影响。结果表明,1300℃以上的退火有利于改善SIMOX(Separation by ImplantedOxygen)材料性能,MOS晶体管具有非常低的漏电流。     

A low thermal budget self-aligned Ti silicide technology usinggermanium implantation for thin-film SOI MOSFET's

In this paper, a titanium salicide technology with a very low thermal annealing temperature using germanium implantation for thin film SOI MOSFET's is investigated in detail. Ti silicide formation on the amorphous silicon generated by germanium implantation is studied. Compared to the conventional Ti salicide process, the Ti silicidation temperature is significantly lowered and the silicide depth is well controlled through the pre-amorphized layer. Therefore, the potential problems of the salicide process for SOI MOSFET's such as lateral voids, dopant segregation, thermal agglomeration, and increase of resistance on narrow gate are suppressed by germanium implantation. With the Ge pre-amorphization salicide process, a very low silicide contact resistance is obtained and sub-0.25-μm SOI MOSFET's are fabricated with good device characteristics     

Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density.The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance-voltage (C-V) analysis.     

Halo注入对50nm NMOS器件性能的影响

利用Sentaurus TCAD软件模拟研究了Halo注入工艺参数(注入角度、剂量、能量)对50nm NMOS器件性能的影响。结果表明,Halo注入角度和剂量的增大会使器件的DIBL特性改善,阈值电压提高;而Halo注入能量的增加会引起器件的DIBL特性变差,阈值电压有所降低,并且较注入角度和注入剂量相比,Halo注入能量的工艺窗口要小。Halo注入参数的变化对Ion和Ioff的影响不同,所以器件开关比随Halo注入角度、剂量和能量的增加呈现非单调性改变。器件的结电容则随Halo注入角度增大而下降,随注入剂量增大而上升,随注入能量的增加先上升后下降。对Halo注入各工艺参数影响器件性能的机理进行了分析,并实验制备了纳米尺度的Halo结构NMOS器件。     

采用局域注氧技术制备的新型DSOI场效应晶体管的热特性

通过局域注氧工艺,在同一管芯上制作了DSOI、体硅和SOI三种结构的器件.通过测量和模拟比较了这三种结构器件的热特性.模拟和测量的结果证明DSOI器件与SOI器件相比,具有衬底热阻较低的优点,因而DSOI器件在保持SOI器件电学特性优势的同时消除了SOI器件严重的自热效应.DSOI器件的衬底热阻和体硅器件非常接近,并且在进入到深亚微米领域以后能够继续保持这一优势.