Ni/Si,Pt/Si,Ir/Si系的As离子注入和退火

本文用RBS,AES,TEM和X射线衍射等实验方法,分析比较了Ni/Si,Pt/Si,Ir/Si系统在室温下As离子混合和热退火的行为.得出在Ni/Si系统中,硅混合量Q_(s1)与剂量Φ的平方根成正比,形成Ni_2Si相.在Pt/Si系中,硅混合量也与剂量的平方根成正比,先后形成Pt_3Si和Pt_2Si相.对Ir/Si系,Q_(s1)与Φ则是线性关系:Q_(s1)=aΦ+b,未测到化学相.实验表明:离子束混合能大大增强金属和硅化物的化学反应.在离子混合和退火形成硅化物的过程中,注入杂质As的分布有显著变化.     

共溅射W-Si薄膜的快速热退火及其热氧化研究

淀积在SiO_2上的共溅射W-Si 薄膜,在高纯N_2中经200—1100℃的10秒钟快速热退火,用转靶X射线衍射、激光喇曼光谱、俄歇电子能谱、扫描电子显微镜、透射电子显微镜、四探针测量等不同手段研究了钨硅化物的形成.565℃退火出现了W_5Si_3相,退火温度高于755℃,稳定相WSi_2形成,但W_5Si_3相并不消失,一直与WSi_2共存.经考查,W_5Si_3的存在并不是由于在薄膜淀积或是退火形成硅化物的过程中引起缺硅而造成的,它对薄层电阻仅起部分影响作用,材料的电学性质最终仍由具有最低电阻率的稳态WSi_2相决定。WSi_2与W_5Si_3相高温热氧化时都不稳定,会分解并被氧化成SiO_2和WO_3。     

氩氧比与退火温度对磁控溅射VO2薄膜结构与电学性能的影响

采用反应直流磁控溅射法,通过调控溅射过程中的氩氧比,在石英玻璃衬底上制备了氧化钒薄膜,研究了溅射气氛及后处理条件对其微结构与电学性能的影响.经450和500℃退火,薄膜中易形成VO2,而550℃退火时薄膜中会形成大量非4价的钒氧化物.薄膜在较高温度500℃下退火时结晶度增加,但薄膜颗粒之间的间隙更为明显,导致电阻率显著提高;同时其电阻率-温度曲线的热滞回线宽度较窄,在加热过程中相转变温度较高.当氩氧比中氧含量增加时,沉积的VO2薄膜中生成了少量非4价的钒氧化物.结果表明,反应磁控溅射法制备的氧化钒薄膜的微结构、电阻率、相变温度等特性与氩氧比和后退火温度密切相关.     

AS离子注入硅化钛自对准MOS器件技术研究

本工作研究了同时形成polycide栅,源/漏硅化钛接触和浅PN结的MOS器件制造技术。实验结果表明,通过硅化钛薄膜注入As,并利用NH_3等离子体辅助热退火(NPTA)工艺,可制备性能良好的MOS晶体管。以注入杂质的硅化钛薄膜作为杂质源,在一次高温退火过程中同时完成杂质的再分布和低电阻率硅化钛的形成,得到结深小于0.1μm,硅化钛电阻率24μΩ·cm。NPTA退火工艺有效地抑制了Ti/Si和Ti/poly-Si固相反应过程中硅化钛的横向生长,从而获得了自对准程度很高的硅化钛接触和互连。     

用于微测辐射热计的氧化矾热敏材料的温度特性

氧化矾作为非制冷微测辐射热计的热敏材料,电阻率p和电阻温度系数TCR(Temperature Coefficient of Resistance)是表征其性能的重要参数.通过对用离子束溅射得到的氧化矾薄膜在相同时间不同温度下的N2+H.退火实验,我们发现氧化矾薄膜的电阻率p和电阻温度系数TCR之问存在着密切的正相关关系,AES结果表明它们的变化对应着氧化矾热敏材料的O/v比例(或氧空位浓度)的变化.这三个参量随着退火温度的改变而变化,在350～500℃的退火温度范围内,我们发现电阻率p,电阻温度系数TCR以及O/V比例随着温度的变化均出现一个峰值.通过对氧化矾的电阻温度特性的分析,我们讨论了氧化矾薄膜的导电机制.我们认为,用本方法制备的氧化矾薄膜在室温下导电的载流子主要来自于相对较深能级杂质的电离.     

硅-金刚石系统的离子束混合和欧姆接触

用离子束混合Si(700A)/C样品,在天然Ⅱb型金刚石上形成了梯度能带接触。选用Ge~+为注入离子,在能量120keV,剂量2.0×10~(16)cm~(-2),温度700℃下进行离子束混合。Rutherford背散射显示:有3—4％的Si与金刚石混合。红外吸收谱发现了Si—C键的形成,这表明形成了Si/SiC/C的梯度结构。Ⅰ—Ⅴ特性说明了离子束混合和高温热退火有助于欧姆接触的形成。而没有经过离子束混合的样品显示了Ⅰ—Ⅴ开路特性。     

氮化硼薄膜的制备和离子注入掺杂

通常人们对氮化硼薄膜的S掺杂,采用的是在氮化硼制备过程中就地掺杂的方法,文中则采用S离子注入方法.氮化硼薄膜用射频溅射法制得.实验结果表明,在氮化硼薄膜中注入S,可以实现氮化硼薄膜的n型掺杂;随着注入剂量的增加,氮化硼薄膜的电阻率降低.真空退火有利于氮化硼薄膜S离子注入掺杂效果的提高.在离子注入剂量为1×1016cm-2时,在600℃的温度下退火60min后,氮化硼薄膜的电阻率为2.20×105 Ω·cm,比离子注入前下降了6个数量级.     

氮化硼薄膜的制备和离子注入掺杂

通常人们对氮化硼薄膜的S掺杂,采用的是在氮化硼制备过程中就地掺杂的方法,文中则采用S离子注入方法.氮化硼薄膜用射频溅射法制得.实验结果表明,在氮化硼薄膜中注入S,可以实现氮化硼薄膜的n型掺杂;随着注入剂量的增加,氮化硼薄膜的电阻率降低.真空退火有利于氮化硼薄膜S离子注入掺杂效果的提高.在离子注入剂量为1×1016cm-2时,在600℃的温度下退火60min后,氮化硼薄膜的电阻率为2.20×105 Ω·cm,比离子注入前下降了6个数量级.     

钽掺杂对二氧化钒多晶薄膜相变特性的影响

将Ta_2O_5与V_2O_5均匀混合,压制成溅射靶,用离子束增强沉积方法在二氧化硅衬底上沉积掺Ta氧化钒薄膜.在氮气中适当退火,形成掺杂二氧化钒多晶薄膜.X射线衍射结果显示,薄膜具有单一的(002)取向.XPS测试表明,膜中V为+4价,Ta以替位方式存在.温度-电阻率测试表明,薄膜具有明显的相变行为,原子比为3%的Ta掺杂后,二氧化钒多晶薄膜相变温度降低到约48℃.Ta原子的半径大于V原子的半径,Ta的掺入在薄膜中引入了张应力;5价Ta 替代4价V,在d轨道中引入多余电子,产生施主能级,这些是掺钽二氧化钒多晶薄膜相变温度降低的原因.     

氮化硼薄膜的制备和离子注入掺杂

通常人们对氮化硼薄膜的S掺杂，采用的是在氮化硼制备过程中就地掺杂的方法，文中则采用S离子注入方法. 氮化硼薄膜用射频溅射法制得. 实验结果表明，在氮化硼薄膜中注入S，可以实现氮化硼薄膜的n型掺杂；随着注入剂量的增加，氮化硼薄膜的电阻率降低. 真空退火有利于氮化硼薄膜S离子注入掺杂效果的提高. 在离子注入剂量为1E16cm-2时，在600℃的温度下退火60min后，氮化硼薄膜的电阻率为2.20E5Ω·cm，比离子注入前下降了6个数量级.     

高温退火对PECVD硅化钛膜的影响

<正> 一、引言 以TiSi_2为代表的难熔金属硅化物,由于具有铝及掺杂多晶硅所不具备的特点,已成为VLSI中制作栅电极和互连线的重要材料。CVD法制备硅化钛膜的突出优点是台阶覆盖性好,有利于批量生产。然而,用卧式PECVD制备硅化钛膜的方法至今尚未见报道。 PECVD法淀积的硅化钛膜,必须经退火结构才能稳定。目前,常用瞬态退火和常规热退火(高温退火)两种方法。常规热退火能和常规工艺兼容,而瞬态退火则可减少原子的互扩散。 笔者用平板型PECVD设备,在典型工艺条件下淀积了薄膜,分析了高温退火对薄膜电阻率、组分、结构的影响。     

固相反应和离子注入制备硅化镍薄膜

采用固相反应和镍离子注入硅方法分别制备了硅化镍薄膜，利用卢瑟福背散射谱（RBS) , X射线衍射（XRD）和喇曼光谱对它们的成分和结构进行了表征. 结果表明固相反应方法中，硅化镍薄膜的相结构取决于不同的热退火条件，纯相的NiSi2薄膜需要在高温（1123K）下两步热退火才能获得. 而利用离子注入方法，则可以在较低温度（523K）下直接得到单相的NiSi2薄膜. 在30～400K范围内测量了它们的电阻率和霍尔迁移率随温度的变化关系，结果表明固相反应制备的NiSi和NiSi2薄膜都表现出典型的金属性电导行为，而离子注入制备的NiSi2薄膜则表现出完全不同的电学性质.     

The process window of a-Si/Ti bilayer metallization for anoxidation-resistant and self-aligned TiSi2 process

The dependences of both oxidation-resistant and self-aligned silicidation properties on the thicknesses of top amorphous-Si (a-Si) and Ti metal in an a-Si/Ti bilayer process are presented. It is shown that a thin silicide layer formed during the reaction between a-Si and Ti films becomes a stable oxidation and nitridation barrier for oxygen- and nitrogen-related impurities. Moreover, the formation sequence of the silicide phase depends not only on the annealing temperature but also on the thickness of the Ti film. In addition, the preferential orientation of the silicide phase after annealing at high temperature also shows a strong dependence on the thickness of Ti film, which is attributed to the difference of the grain size in the polycrystalline silicide film. The allowed process window for the a-Si thickness can be determined experimentally and a reproducible and homogeneous self-aligned TiSi₂ film can be easily obtained by using the a-Si/Ti bilayer process in salicide applications despite high-level contaminations of oxygen impurities in both the as-deposited Ti film and the annealing ambient     

Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi₂) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi₂ films. A Ge⁺ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge⁺ ion mixed and unmixed thin CoSi₂ layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (<50 nm) CoSi₂ preparation. A comparison of the plan-view and cross-section TEM micrographs of the ion-beam mixed and unmixed CoSi₂ films reveals that Ge⁺ ion mixing (45 keV, 1 × 10¹⁵ cm⁻²) produces homogeneous silicide with smooth silicide-to-silicon interface.     

Arsenic redistribution induced by low-temperature Ni silicidation at 450°C on shallow junctions

Redistribution of arsenic (As) during silicidation of a 13-nm Ni film on an n⁺/p junction at 450°C is investigated. NiSi formation is observed by x-ray diffraction, micro-Raman scattering spectroscopy, and Rutherford backscattering spectroscopy (RBS). Both secondary ion mass spectroscopy and RBS data indicate the redistribution and accumulation of As into two layers after the low-temperature annealing. The deeper accumulation peak, located just near the silicide/silicon interface, is attributed to As segregation from silicide into Si substrate. The shallower accumulation peak is located in a vacancy-cluster layer several nanometers below the silicide film surface. The vacancy-cluster layer, characterized by cross-sectional transmission electron microscopy, separates the silicide film into two layers, and is attributed to the well-known Kirkendall effect.     

La,Ce及Nd稀土金属硅化物的生成

用AES,X-射线衍射和RBS等方法分析研究了热反应与离子束混合La,Ce及Nd稀土金属膜和硅反应生成硅化物的物理过程。实验表明:不同的生成条件如热反应温度或离子束混合的剂量能生成富金属硅化物,单硅化物和二硅化物,但最终稳定相都是二硅化物LaSi_2,CeSi_2和NdSi_2。氧的沾污不但影响生成的硅化物相和质量,甚至阻止硅化物的生成。镀膜时的衬底温度和防止氧化的保护层对硅化物薄膜的质量,平整度,均匀性等都有明显的影响。     

Thermal stability of Cu(W) and Cu(Mo) films for advanced barrierless Cu metallization: Effects of annealing time

The current study investigates the effects of insoluble substances (W and Mo) in pure Cu films on the thermal stability, microstructure, and electrical properties of the films. The results can be used to assess the feasibility of the barrierless Cu film in the metallization process. The films investigated were deposited using magnetron sputtering onto the barrierless Si (100) substrate and then annealed between 400°C and 450°C in vacuum for long periods of time. After annealing, the film properties were examined by x-ray diffraction (XRD), the four-point probe method, leakage current measurements, and focused ion beam (FIB) analysis. The results indicate that no detectable copper silicide is formed after 48-h annealing of Cu(W) films at 400°C. In contrast, for the Cu(Mo) film, copper silicide is formed after 18-h annealing at the same temperature and hence electrical properties are poor. This evidence suggests that the Cu(W) film has better thermal stability during long periods of annealing and is suitable for an advanced barrierless metallization process.     

氧化钒热敏薄膜的制备及其性质的研究

报道一种制备氧化钒热敏薄膜的新方法。采用离子束溅射V2O5粉末靶淀积和氮氢混合气体热处理相结合的薄膜技术,可制备热敏性能较好的低价氧化钒薄膜VOx(x＜2.5)。对不同温度退火后氧化钒薄膜在10－100℃范围内测定了薄层电阻随温度的变化,得到的电阻温度系数（TCR）值为（－1～－4）％K^-1。研究结果表明通过这种方法可在较低温度下制备氧化钒薄膜,这种薄膜具有较低的电阻率和较高的TCR值,可作为非致冷红外微测辐射热计的热敏材料。     

Formation of cobalt silicided shallow junction using implantinto/through silicide technology and low temperature furnace annealing

This work investigates the shallow CoSi₂ contacted junctions formed by BF₂⁺ and As⁺ implantation, respectively, into/through cobalt silicide followed by low temperature furnace annealing. For p⁺n junctions fabricated by 20 keV BF₂⁺ implantation to a dose of 5×10¹⁵ cm^-2, diodes with a leakage current density less than 2 nA/cm² at 5 V reverse bias can be achieved by a 700°C/60 min annealing. This diode has a junction depth less than 0.08 μm measured from the original silicon surface. For n⁺p junctions fabricated by 40 keV As⁺ implantation to a dose of 5×10¹⁵ cm^-2, diodes with a leakage current density less than 5 nA/cm² at 5 V reverse bias can be achieved by a 700°C/90 min annealing; the junction depth is about 0.1 μm measured from the original silicon surface. Since the As⁺ implanted silicide film exhibited degraded characteristics, an additional fluorine implantation was conducted to improve the stability of the thin silicide film. The fluorine implantation can improve the silicide/silicon interface morphology, but it also introduces extra defects. Thus, one should determine a tradeoff between junction characteristics, silicide film resistivity, and annealing temperature     

Sputtered copper films with insoluble Mo for Cu metallization: A thermal annealing study

The thermal annealing behavior of Cu films containing insoluble 2.0 at. % Mo magnetron co-sputtered on Si substrates is discussed in the present study. The Cu-Mo films were vacuum annealed at temperatures ranging from 200°C to 800°C. X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations have shown that Cu₄Si was formed at 530°C, whereas pure Cu film exhibited Cu₄Si growth at 400°C. Twins are observed in focused ion beam (FIB) images of as-deposited and 400°C annealed, pure Cu film, and these twins result from the intrinsically low stacking-fault energy. Twins appearing in pure Cu film may offer an extra diffusion channel during annealing for copper silicide formation. In Cu-Mo films, the shallow diffusion profiles for Cu into Si were observed through secondary ion mass spectroscopy (SIMS) analysis. Higher activation energy obtained through differential scanning calorimetry (DSC) analysis for the formation of copper silicide further confirms the beneficial effect of Mo on the thermal stability of Cu film.