钝化膜应力对锑化铟器件性能的影响

随着InSb红外探测器关键尺寸的不断缩小,钝化膜应力的大小对器件I-V性能的影响越发明显。为了降低探测器芯片的应力,研究了一种由SiO₂ 和SiON组成的复合钝化膜体系。通过改变气体的射频时间,在InSb晶片上淀积厚度分别为300 nm、500 nm、700 nm和900 nm的钝化膜,测量并计算了不同厚度钝化膜的应力。当厚度为700 nm时,钝化膜的应力最小值为－1.78 MPa。研究了具有不同应力钝化膜的器件的I-V特性,发现厚度为700 nm时InSb芯片具有更加优异的I-V特性。通过调整复合钝化膜的厚度,降低了钝化膜的应力,有效地提升了InSb探测器的性能。     

0.18μm BCD工艺平台LogicEE IP的数据保持力

研究表明,0.18μm BCD工艺中SAB膜的厚度对Logic EE IP的数据保持力特性有重大影响。SAB膜越厚,Logic EE IP的数据保持力特性越好;如果SAB膜厚度小于一定尺寸,那么Logic EE IP的数据保持力将会失效。因此适当的SAB膜厚度对保证Logic EE IP的数据保持力通过合格性测试非常重要。主要研究在标准工艺条件下,通过3种SAB膜厚(标准厚度55 nm、80 nm和100 nm)、老衬底(标准厚度55 nm)、新衬底延长清洗时间(标准厚度55 nm)以及新衬底新生长材料的SAB膜(标准厚度55 nm)等试验,最终确定了在华虹宏力0.18μm BCD工艺平台上,当SAB膜厚度为100 nm时,Logic EE IP核的数据保持力通过了JEDEC标准的合格性测试。     

引线框氧化与可靠性关系的研究

铜材料引线框架具有良好的导电导热性能,同时具备良好的机械性能和较低成本,但是由于框架和塑封料之间较差的粘结力在回流焊时容易造成封装体开裂。文章研究了铜框架氧化膜的特性,以及氧化膜对半导体封装的可靠性影响。根据试验,氧化膜会随着时间温度而增加,当氧气含量低于1%时增加缓慢。当氧化膜的厚度超过20nm时,塑封料与氧化铜之间的结合力就会显著下降,同时交界面的分层也会加剧。最后针对氧化膜厚度受控的产品做回流焊测试,确认是否有开裂,结果表明与结合力测试相符。氧化膜的厚度需要低于42.5nm,可以提高在reflow时的抗开裂性能。     

台积电发布28nm工艺首次采用了高-k和HKMG技术

日前,台积电发布了28nm工艺技术。该技术采用193nm的液浸光刻,并首次采用HKMG技术。晶体管的栅长最短为24nm。EOT（等效氧化膜厚度）为0．9nm,与该公司在07年IEDM上发布的未采用HKMG的32nm工艺技术的EOT值1．6nm相比,大幅削减了厚度。     

纳米Al夹层Ga_2O_3深紫外透明导电膜的研究

用磁控溅射法在室温条件下制备了Al膜、Ga2O3膜及Ga2O3/Al/Ga2O3三层膜,对其光学和电学性能进行了表征。单层Al膜厚度大于7nm时,光学透射率在近紫外光区域大于可见光区域;Ga2O3膜在深紫外光区域(<300nm)透明,光学带隙4.96eV;Ga2O3/Al/Ga2O3三层膜透射率截止波长在245nm左右,随着顶层Ga2O3厚度增加,电导率减小,紫外光透射率峰位、吸收边、截止波长红移,透射率峰值先稍微增加,然后逐渐降低。顶层Ga2O3厚度为34nm时,Ga2O3/Al/Ga2O3三层膜在275nm处的透射率达70%,电导率为3346S.cm–1。     

碲镉汞阳极氧化膜界面的研究

用X射线光电子能谱方法研究了Hg_0.8CD_0.2Te样品的厚度为35、50、55、和65nm的阳极氧化膜。结果表明阳极氧化膜的成分中:0为58～60%,Te为22～26%,Cd为10～13%,Hg为3～4%。在氧化膜与基体界面半导体一侧存在缺汞区,比正常值少14～34%。     

一种制备氧化钒薄膜的新工艺

采用两步法工艺,即先在衬底上溅射一层金属钒膜,再对其进行氧化的方法,在硅和氮化硅衬底上制备了高电阻温度系数的混合相VOx多晶薄膜。电学测试结果表明:厚度为50nm的氧化钒薄膜的方块电阻和电阻温度系数(TCR)在室温时分别达到50kΩ和0.021K-1。     

纳米Mo膜的光学特性及最小连续膜厚研究

利用Lambda-900分光光度计，在波长为310～1250nm范围内测量了离子束溅射沉积不同厚度纳米Mo膜的反射率和透射率。选定波长为310nm，350nm，400nm，500nm，550nm，632nm，800nm，1200nm时对薄膜的反射率、透射率和吸收率随膜厚变化的关系进行了讨论。实验结果显示，纳米Mo膜的光学特性有明显的尺寸效应。提出将薄膜对光波长为550nm时的反射率和透射率随Mo膜厚度变化关系的交点对应的厚度作为特征厚度，该厚度可认为是纳米Mo膜生长从不连续膜进入连续膜的最小连续膜厚。利用原子力显微镜(AFM)观测膜厚在15．76nm时的表面形貌，此时表面形貌已呈现连续膜的特征。     

沟槽栅功率器件栅氧化膜特性的工艺研究

本文分析了沟槽栅功率器件中对栅氧化膜特性造成影响的主要工艺因素,报告了一种获得高性能栅氧特性的方法,并且对栅氧化膜特性改善的机理进行了研究。对于厚度55nm的沟槽栅氧化膜,其正向偏置和反向偏置下的击穿电压都高于30伏特。     

航空钛合金梯度改性修复层抗高温氧化性能研究

研究了航空钛合金损伤结构梯度改性修复层和Ti600基体在800 ℃下的氧化行为; 采用恒温或循环氧化增重法、氧化速度常数、活度等理论计算研究了氧化的热力学和动力学规律; 利用扫描电镜(SEM)和X射线衍射(XRD)等分析了氧化膜形貌和组成。结果表明: 梯度修复层有较好的抗氧化性能, 其循环氧化动力学曲线基本符合抛物线规律; Ti600基体属次抗氧化级, 其循环氧化动力学曲线近似符合抛物线-直线规律; 梯度修复层氧化膜由金红石结构的TiO2和少量Cr2O3组成, 厚度5～6 μm, 与基体连接紧密, 且致密、连续, 为短纤维状组织; Ti600基体的氧化膜厚度达55 μm左右, 明显分为内氧化区、中致密层和外疏松多孔层, 为多面体规则形状组织。     

Anticipation of nitrided oxides electrical thickness based on XPS measurement

Plasma nitridation of thermally grown oxide films has proven to be an excellent gate dielectric in meeting the electrical requirements of the 65 nm node. As the 65 nm device performance is very sensitive to both physical thickness and nitrogen dose of these dielectric films, it is highly desirable to predict the electrical properties of such films. We present a simple physical model to forecast the capacitance-equivalent thickness (CET) of nMOS devices for 65 nm technology. The model is based on the total nitrogen dose and the dielectric physical thickness, both given by in-line X-ray photoelectron spectroscopy (XPS) measurement of the plasma nitrided gate dielectric. This model uses an estimated gate oxide dielectric constant, the gate depletion capacitance and the inversion layer capacitance. A good correlation is obtained between calculated and measured CET for plasma nitrided oxides from 19 to 30 Å CET and for a large range of incorporated nitrogen doses.     

Characteristics of the NO dielectric film with low pressure chemical vapor deposition in-situ nitridation

We investigated the formation of the thin NO dielectric films by in-situ nitridation of native oxide, and subsequent deposition of silicon nitride in the low pressure chemical vapor deposition systems for the application to the capacitors in high density dynamic random access memory. The native oxide was nitrided at elevated temperatures of 690 or 780°C in the flowing ammonia gas atmosphere, and nitride was deposited by flowing silane gas additionally immediately after the nitridation process. By in-situ nitridation process, we could obtaine 5 and 4.5 nm thick (equivalent oxide thickness) nitride/oxide (NO) dielectric films. These films were characterized to be electrically more reliable than the conventional oxide/nitride/oxide (ONO) films of the same equivalent oxide thickness. The nitrided NO films also showed lower leakage current and higher breakdown voltage than conventional ONO films. We obtained electrically most reliable NO films by loading the wafer at 400°C and nitriding the native oxide at 780°C.     

Correlation between reliability and oxidation temperature for ultra-dry ultrathin silicon oxide films

The correlation between time-dependent dielectric breakdown lifetime and oxidation temperature of 800–950°C for 3.5 and 5.0 nm thick silicon oxide films as gate insulators was investigated. To obtain ideal gate oxide films with few hydrogen-related defects and precise thickness distribution that extremely influence the lifetime, metal-oxide semiconductor diodes with the films used in the evaluation were produced by our continuous ultra-dry process. The films oxidized at 850°C showed the largest lifetimes irrespective of thickness. The enhancement, however, was confirmed only in the diodes selecting the oxidesilicon substrate interfaces as the anode-side, where the lifetime is mainly dominated. Interestingly, a similar relationship was observed in their density characteristics. This suggests that the condition near the oxide-silicon substrate interfaces is probably improved by the 850°C oxidation due to microscopic structural changes.     

膜厚对氧化钒薄膜结构和光学性质的影响

利用真空热蒸发在石英基片上制备了不同厚度的氧化钒薄膜, 研究厚度对薄膜的结构、形貌和光学特性的影响。薄膜的结构由X射线衍射(XRD)仪和拉曼(Raman)光谱仪测得, 表面形貌用原子力显微镜(AFM)观测。利用分光光度计测量薄膜的光学透射率, 并且采用Forouhi-Bloomer模型与修正的德鲁德(Drude)自由电子模型相结合的方法拟合透射率来确定薄膜的折射率、消光系数和带隙。结果表明, 热蒸发的氧化钒薄膜呈非晶态, 薄膜的主要成分为五氧化二钒, 且含有少量的二氧化钒。薄膜表面的颗粒粘结在一起, 随着薄膜厚度的增加, 薄膜表面粗糙度以及颗粒尺寸变小, 膜层表面平整度越来越好, 颗粒之间的空隙变小, 导致折射率随膜厚的增加而增大, 消光系数减小。另外, 随着薄膜厚度从200 nm增加到450 nm, 光学带隙从2.67 eV减小到2.45 eV。     

超声雾化喷涂工艺及优质二氧化锡透明导电薄膜的研究

报道了采用超声雾化喷涂工艺沉积优质掺杂二氧化锡透明导电半导体薄膜的实验成果 ,选用氟作为掺杂元素 ,通过改变掺杂量和工艺参数 ,可控制薄膜的方块电阻在 1 0 Ω/□以上的范围内变化 (40 0 nm膜厚 ) ,掺氟离子二氧化锡为 n型导电半导体 ,高浓度掺杂的二氧化锡薄膜光学透过率为 87%～ 90 % (采用 550 nm单色光源测透过率 )。用 X射线衍射及扫描电子显微镜分析 ,可获得该薄膜材料的微结构、表面形貌以及薄膜组成、掺杂百分含量。该成果为大规模生产优质二氧化锡透明导电薄膜 ,提供了有效、简单的方法和装置。     

铝阳极氧化膜多孔质结构的电镜研究

本文针对研究开发新型自润滑阳极氧化铝功能材料的要求，用ＴＥＭ系统考察了在二种不同酸性溶液中生成的铝阳极氧化膜的微观多孔质结构，确定了孔的形态和孔隙率；并用电子束诱导结晶化的方法￣［１］确定了铝阳极氧化膜的物相结构为非晶态ｒ－Ａｌ＿２Ｏ＿３。此外，还用ＨＲＥＭ对阳极氧化膜与铝底材之间的界面进行了研究，发现了过渡层的存在，过渡层厚约４ｎｍ。     

缓冲层厚度对透明导电薄膜ZnO:Zr性能的影响

利用直流磁控溅射法在有ZnO:Zr缓冲层的水冷玻璃衬底上成功制备出了ZnO:Zr透明导电薄膜,缓冲层的厚度介于35～208 nm.利用XRD、SEM、四探针测试仪和紫外-可见分光光度计研究ZnO:Zr薄膜的结构、形貌、电光性能.结果表明,薄膜的颗粒尺寸和电阻率对缓冲层厚度具有较强的依赖性.当缓冲层厚度从35 nm增加到103 nm时,薄膜的颗粒尺寸增大,电阻率减小.而当缓冲层厚度从103 nm增加到208 nm时,薄膜的颗粒尺寸减小,电阻率增大.当缓冲厚度为103 nm时,薄膜的电阻率最小为2.96×10-3 Ω·cm,远小于没有缓冲层时的12.9×10-3 Ω·cm.实验结果表明,在沉积薄膜之前先沉积一层适当的缓冲层是提高ZnO:Zr薄膜质量的一种有效方法.     

硅上后热氧化钛膜制备氧化钛及其电学特性

采用在硅上磁控溅射金属钛膜再热氧化的工艺制备了多晶氧化钛薄膜.测量了Ag/TiOx/Si/Ag电容器的I-V和C-V特性.结果表明,氧化钛薄膜的厚度为150～250nm,其介电常数是40～87.随着氧化时间的缩短,氧化钛薄膜中的固定电荷减少,漏电特性得到改善.     

直流磁控溅射法低温制备ZnO:Ti透明导电薄膜及特性研究

利用直流磁控溅射法在室温水冷玻璃衬底上制备出了可见光透过率高、电阻率低的掺钛氧化锌(ZnO:Ti)透明导电薄膜.SEM和XRD研究结果表明,ZnO:Ti薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向.厚度为437 nm薄膜的电阻率为1.73×10~(-4) Ω·cm.所制备薄膜具有良好的附着性能,薄膜样品在500～800 nm的可见光平均透过率都超过了91%.     

Structural and chemical characterization of as-deposited microcrystalline indium oxide films prepared by dc reactive magnetron sputtering

Microcrystalline indium oxide (InO_x) films with thickness of 120–1600 nm were prepared by dc reactive magnetron sputtering in various mixtures of oxygen in argon at room temperature. The depositions were carried out onto Corning 7059 glass and silicon substrates. The conductivity of the as-deposited films can change in a controllable and fully reversible manner by about six orders of magnitude by alternately exposing the films to ultraviolet (UV) light (hv≥3.5eV) in vacuum and reoxidizing them in ozone. The microstructure of the films was investigated using transmission electron microscopy (TEM) and electron diffraction. For this purpose, films with a thickness of about 100 nm were deposited onto NaCl substrates. The surface and depth composition of the films were examined using Auger electron spectroscopy (AES) combined with depth profiling analysis. The depth profiles showed that all the films exhibit an extremely good in-depth uniformity, all the way to the interface with the glass substrate, regardless of their thickness. Quantitative Auger and energy dispersive x-ray (EDX) analyses were employed to determine the stoichiometry of the films. An oxygen deficiency of 2–5% has been observed with respect to the stoichiometric composition. The effects of film thickness and oxygen content in the sputtering gas on the stoichiometry were examined. Both AES and EDX analyses confirmed that the stoichiometry is invariant for these parameters.