HMDSO Polymer 各种膜应用
聚合物成膜剂

聚合物成膜剂
聚合物成膜剂是一种添加到涂料中的化学物质,它能够在涂料干燥后形成一个坚硬、耐磨损的薄膜。
这种薄膜具有良好的耐水性、耐化学性和耐紫外线性能,可以保护被涂物表面不受外界环境的侵害。
聚合物成膜剂通常是由聚合物单体、交联剂、助剂等组成的。
其中,聚合物单体是形成聚合物分子链的基本单元,可以选择不同种类的单体来制备不同性质的聚合物;交联剂则可以将不同聚合物分子链相互连接,提高其机械强度和耐久性;助剂则能够调节涂料流变性能、改善其附着力等。
在实际应用中,聚合物成膜剂广泛用于各种类型的涂料中,如油漆、清漆、墙面涂料等。
通过添加适量的聚合物成膜剂到涂料中,可以显著提高其表面硬度和光泽度,并增强其抗水、抗化学品和抗紫外线的能力。
此外,聚合物成膜剂还可以用于制备高分子材料、粘合剂等领域。
总之,聚合物成膜剂是一种非常重要的化学品,它在涂料和高分子材料等领域中具有广泛的应用前景。
随着科技的不断进步,我们相信聚合物成膜剂会越来越多地被应用于各种新型材料和涂料中,为人们创造更加美好的生活。
高迁移率聚合物半导体材料最新进展

高迁移率聚合物半导体材料最新进展高迁移率聚合物半导体材料(High-Mobility Polymer Semiconductors)在有机半导体材料领域备受关注。
随着电子设备的不断普及,有机半导体材料的应用越来越广泛。
提高高迁移率聚合物半导体材料的性能,可实现更高效能的电子设备。
高迁移率聚合物半导体材料具有高度的柔性和可塑性,可以制成多种形状和尺寸的器件,满足不同应用领域的需求。
其电性能强,可作为有机场效应管(Organic Field Effect Transistor,OFET)的材料。
为了提高高迁移率聚合物半导体材料的性能,研究人员通过不断的改进制备工艺和材料的化学结构,进一步提高了材料的场效应迁移率。
目前,研究人员在提高高迁移率聚合物半导体材料的性能方面,已取得了很大的进展。
首先,制备工艺方面,利用蒸气氧化(Vapor Oxidation)、操作温度和结晶度的控制等技术,可以大大提高材料的性能。
蒸气氧化法可以改善材料的表面形貌和结晶度,使其场效应迁移率得到提高。
同时,合理控制操作温度和结晶度,可以提高高分子聚合物材料的有序程度,进一步提高迁移率。
其次,化学结构方面,研究人员可以通过结构改变等手段,进一步提高材料的场效应迁移率。
随着越来越多的基于半导体高分子的研究,人们逐渐认识到材料分子结构的微小改变可以影响其能带结构和局域状态,从而影响材料的电学性能。
在这一背景下,研究人员引入多种有机精细修饰的方法,例如较小的分子构筑(Small Molecule Building),和基于有机框架的方法,如嵌段共聚物法。
最后,与有机杂化半导体的研究结合,研究人员已经开始探索不同介质(如氧、水以及某些金属离子等)对有机杂化半导体材料性能的影响。
因此,有组合不同材料制备复合材料等方法,使材料具有更好的电性能和物理性能,并且提高其实用性,因而具有重要的现实意义。
聚合物成膜剂

聚合物成膜剂聚合物成膜剂是一种广泛应用于化工、建筑、医药等领域的化学品。
它是一种能够形成无色透明、坚韧耐用的薄膜材料,具有优异的机械性能和化学稳定性。
聚合物成膜剂的主要成分是高分子化合物,其中包括丙烯酸酯类、乙烯酸酯类、丁基橡胶等多种材料。
聚合物成膜剂的应用十分广泛。
在建筑领域中,它常被用于墙面涂料、地坪涂料、防水涂料等方面。
这些涂料可以为建筑物提供优异的防水、防潮、防腐、耐磨等性能。
在医药领域中,聚合物成膜剂被广泛应用于药物包衣、口腔贴片、胶囊等方面。
这些应用可以保证药物在口腔、胃肠道中的释放速度、药效等方面的稳定性和可控性。
聚合物成膜剂的制备主要有自由基聚合法、离子聚合法、溶液聚合法等多种方法。
其中,自由基聚合法是应用最为广泛的方法之一。
自由基聚合法通过在交联剂的存在下,将单体聚合成高分子链,最终形成坚韧的聚合物薄膜。
这种方法制备的聚合物成膜剂具有较高的交联度和分子量,因此具有更好的力学性能和化学稳定性。
聚合物成膜剂的性能与结构密切相关。
一般来说,聚合物成膜剂的分子量越高,交联度越大,形成的膜层越厚实、坚韧、稳定。
同时,聚合物成膜剂的结构还与其应用性能密切相关。
例如,丙烯酸酯类聚合物成膜剂具有优异的附着性和耐久性,适用于制备高质量的墙面涂料、地坪涂料等;乙烯酸酯类聚合物成膜剂具有良好的透气性和弹性,适用于制备口腔贴片等;丁基橡胶聚合物成膜剂具有优异的耐化学品性能,适用于制备化学涂料、胶水等。
聚合物成膜剂是一种十分重要的化学品,在建筑、医药、化工等领域都有广泛的应用。
聚合物成膜剂的性能与结构密切相关,不同类型的聚合物成膜剂适用于不同的应用场合。
随着技术的不断进步,聚合物成膜剂的应用前景将会更加广阔。
聚醚膜规格

聚醚膜规格摘要:一、聚醚膜简介1.聚醚膜的概念2.聚醚膜的分类二、聚醚膜规格参数1.厚度2.宽度3.长度4.密度5.抗拉强度6.耐热性三、聚醚膜的应用领域1.电子行业2.食品包装3.医疗用品4.化工行业5.其他领域四、聚醚膜的优缺点1.优点a.良好的物理性能b.化学稳定性c.生物相容性d.环保可降解2.缺点a.耐磨性较差b.成本较高正文:聚醚膜是一种具有特殊性能的聚合物材料,以聚醚为主要原料,通过特定的工艺制成。
聚醚膜具有良好的物理性能、化学稳定性和生物相容性,被广泛应用于各个领域。
一、聚醚膜简介聚醚膜是一种高分子材料,具有独特的性能。
它是一种非晶态的弹性聚合物,具有一定的柔软性、韧性和强度。
聚醚膜可以根据原料和生产工艺的不同,分为多种类型。
二、聚醚膜规格参数聚醚膜的规格参数包括厚度、宽度、长度、密度、抗拉强度和耐热性等。
这些参数可以根据实际应用需求进行调整,以满足不同场景的要求。
三、聚醚膜的应用领域聚醚膜具有广泛的应用领域,如电子行业、食品包装、医疗用品、化工行业等。
在电子行业中,聚醚膜可用作绝缘材料、散热材料等;在食品包装中,聚醚膜可作为保鲜膜、阻隔膜等;在医疗用品中,聚醚膜可制作成医用口罩、创可贴等;在化工行业中,聚醚膜可用于防腐、防水等领域。
四、聚醚膜的优缺点聚醚膜具有许多优点,如良好的物理性能、化学稳定性、生物相容性和环保可降解性。
然而,它也存在一些缺点,如耐磨性较差、成本较高。
因此,在选择聚醚膜时,需要根据实际需求权衡其优缺点。
总之,聚醚膜作为一种具有优良性能的材料,在多个领域有广泛的应用。
常见电热膜基材

常见电热膜基材电热膜是一种能够产生辐射热的薄膜材料,广泛应用于家电、汽车和工业领域。
作为电热膜的基材,有几种常见的材料,包括聚酰亚胺膜、聚酰胺膜、聚酯膜、聚四氟乙烯膜等。
1. 聚酰亚胺膜聚酰亚胺膜是一种高性能的电热膜基材,具有优异的绝缘性能、高温耐性和化学稳定性。
它能够承受高温达到200摄氏度以上,同时具有较低的热膨胀系数和良好的机械强度。
这使得聚酰亚胺膜成为电热膜的理想基材之一。
2. 聚酰胺膜聚酰胺膜是一种具有良好机械性能和电绝缘性能的电热膜基材。
它具有较高的化学稳定性和耐磨性,能够在较宽的温度范围内使用。
聚酰胺膜的热导率相对较低,可以有效地减少能量损耗,提高电热膜的效率。
3. 聚酯膜聚酯膜是一种常见的电热膜基材,具有较好的机械强度和柔韧性。
它具有良好的耐热性和化学稳定性,可以在较高的温度下工作。
聚酯膜还具有较低的热膨胀系数和良好的电绝缘性能,使其成为电热膜的理想选择。
4. 聚四氟乙烯膜聚四氟乙烯膜是一种耐高温、耐腐蚀的电热膜基材。
它具有优异的绝缘性能和化学稳定性,可以在较恶劣的工作环境下使用。
聚四氟乙烯膜的表面具有较低的表面粗糙度和良好的抗粘性能,能够有效减少电热膜与其他材料之间的摩擦和粘附。
总结起来,常见的电热膜基材包括聚酰亚胺膜、聚酰胺膜、聚酯膜和聚四氟乙烯膜。
这些基材具有不同的特点和适用范围,可以根据具体的应用需求选择合适的材料。
电热膜的基材选择对于电热膜的性能和稳定性具有重要影响,因此在电热膜的设计和制造过程中需要充分考虑基材的选择和特性。
未来,随着材料科学的发展和技术的进步,电热膜基材的种类和性能将会不断提升,为电热膜的应用提供更多可能性。
聚甲基丙烯酸用途

聚甲基丙烯酸用途1.膜材料:聚甲基丙烯酸具有良好的柔韧性和耐磨性,使其成为制备薄膜材料的理想选择。
聚甲基丙烯酸薄膜广泛应用于液晶显示器(LCD),光伏电池,电容器等领域。
其高透明度和低折射率使其非常适合用于光学器件的保护和增强。
2.丙烯酸凝胶:在医疗领域,聚甲基丙烯酸衍生物被广泛用于制备丙烯酸凝胶。
这些凝胶可以用作创伤敷料,药物缓释系统和组织工程支架。
丙烯酸凝胶具有良好的生物相容性,可以提供潮湿的环境促进伤口愈合,并且可以通过控制交联程度和孔隙结构来调节药物缓释速度。
3.水性乳液:聚甲基丙烯酸可以与其他聚合物(如聚乙烯醇)共聚合形成水性乳液。
这些乳液广泛用于涂料,胶黏剂和油墨等应用中。
由于其低毒性和环保性,水性乳液正在成为替代传统有机溶剂的首选材料。
4.芳香树脂:聚甲基丙烯酸还可以与芳香族单体(如乙烯苯)共聚合形成芳香树脂。
这些树脂具有良好的耐溶剂性和热稳定性,可以用于制备油漆,涂料,粘合剂和塑料。
5.皮革辅料:聚甲基丙烯酸可以用作皮革辅料的成膜剂。
在加工过程中,聚甲基丙烯酸形成一层薄膜,可以提高皮革的强度,耐磨性和防水性。
此外,聚甲基丙烯酸还可以用于制备皮革染色剂和涂料。
6.陶瓷增强剂:添加聚甲基丙烯酸可以显著提高陶瓷材料的断裂韧性和强度。
聚甲基丙烯酸可作为陶瓷基体的增强剂,能够增加材料的可加工性和抗冲击性。
这使得陶瓷材料在复杂结构和高负荷应用中更加耐用。
7.涂层剂:聚甲基丙烯酸可以用作涂层剂的成膜剂。
这些涂层通常应用于建筑、汽车、电子和包装行业。
聚甲基丙烯酸涂层可以提供优良的抗紫外线和耐卡溶剂性能,同时能够有效保护基材。
总结起来,聚甲基丙烯酸是一种多功能的聚合物材料,具有广泛的应用领域。
它在膜材料、医疗领域、乳液、芳香树脂、皮革辅料、陶瓷增强剂和涂层剂等方面发挥着重要作用。
随着科学技术的不断发展,聚甲基丙烯酸的新应用也将不断涌现。
甲基丙烯酸二甲氨基乙酯 聚合物

甲基丙烯酸二甲氨基乙酯聚合物
甲基丙烯酸二甲氨基乙酯聚合物是由甲基丙烯酸二甲氨基乙酯(Methacrylic Acid Dimethylaminoethyl Ester,简称DM-MMA)通过聚合反应得到的高分子化合物。
它是一种有机合成材料,具有较高的聚合度和分子量。
甲基丙烯酸二甲氨基乙酯聚合物具有多种特性和应用。
其中主要特性包括:
1. 良好的热稳定性:可在较高温度下使用,不易分解。
2. 耐溶剂性:对多种有机溶剂具有较好的稳定性,不易溶解或膨胀。
3. 高粘度:具有较高的流变性,可用于增稠剂和粘合剂等应用领域。
4. 反应活性:分子中的酯基和胺基具有反应活性,可进行进一步的官能化改性。
根据其特性,甲基丙烯酸二甲氨基乙酯聚合物在以下领域具有广泛的应用:
1. 油墨和涂料:用作增稠剂、流变剂和粘合剂,提供良好的粘结性和流动性。
2. 建筑材料:用于水泥、石膏和其他建筑材料中的增稠和粘合剂,提高产品的强度和耐久性。
3. 医疗器械:用于制备生物材料和医疗设备,具有生物相容性和可调控的特性。
4. 水处理:用于固体颗粒的离散、水质改善和水处理剂的制备。
5. 电子材料:用于电子封装材料、导电胶和封装胶等应用中,具有良好的粘结性和导电性能。
总而言之,甲基丙烯酸二甲氨基乙酯聚合物是一种具有多种特性和应用的高分子化合物,广泛应用于油墨、涂料、建筑材料、医疗器械、水处理和电子材料等领域。
聚醚膜规格

聚醚膜规格摘要:1.聚醚膜简介2.聚醚膜的规格和分类3.聚醚膜的应用领域4.聚醚膜的性能优势5.聚醚膜的发展趋势和前景正文:聚醚膜是一种具有特殊结构的聚合物膜,以聚醚为主要原料,通过特殊的工艺制成。
它具有良好的化学稳定性、热稳定性和机械强度,被广泛应用于各个领域。
一、聚醚膜简介聚醚膜,又称为聚醚酯膜,是一种高性能的聚合物膜。
它的主要原料是聚醚,经过熔融、挤出、拉伸等工艺过程制成。
聚醚膜具有良好的耐热性、耐化学腐蚀性和机械强度,是一种理想的膜材料。
二、聚醚膜的规格和分类聚醚膜的规格主要取决于其厚度、宽度、长度等几何尺寸。
根据不同的应用需求,聚醚膜可以分为多种类型,如微孔聚醚膜、超微孔聚醚膜、多孔聚醚膜等。
不同类型的聚醚膜具有不同的孔径、孔隙率和过滤效果。
三、聚醚膜的应用领域聚醚膜广泛应用于石油化工、化学、医药、食品饮料、水处理等行业。
具体应用包括:分离、过滤、脱氧、脱臭、催化剂载体等。
聚醚膜在这些领域具有显著的优势,如高过滤精度、低溶出物、耐高温、抗腐蚀等。
四、聚醚膜的性能优势聚醚膜具有以下性能优势:1.良好的化学稳定性:聚醚膜对大多数化学品具有良好的耐受性,不易被腐蚀。
2.热稳定性:聚醚膜具有较高的热稳定性,能在高温环境下保持结构和性能稳定。
3.机械强度:聚醚膜具有较高的抗拉强度和抗弯强度,能承受较大的应力。
4.过滤精度高:聚醚膜具有微孔结构,能实现高过滤精度。
五、聚醚膜的发展趋势和前景随着科技的发展和环境保护意识的提高,聚醚膜在各个领域的应用将越来越广泛。
未来聚醚膜的发展趋势主要表现在以下几个方面:1.开发新型聚醚膜材料,提高膜的性能;2.扩大聚醚膜的应用领域,满足更多行业的需求;3.优化生产工艺,降低生产成本,提高市场竞争力。
总之,聚醚膜作为一种高性能的聚合物膜,具有广泛的应用前景和发展潜力。
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II.1.2.1Bioorganic compounds in primitive earth atmosphereII.1.2.2Methane reformationII.1.2.3Diamond depositionII.1.2.4Action of plasmas on organic moleculesII.1.2.5Plasma etchingII.1.2.6Metal depositionII.1.2.7Metal vapour-non organic moleculesII.1.2.8Si-organic compoundsII.1.2.8.1Plasma polymerizationII.1.2.8.2SiO2depositionII.1.2.9Plasma chemistry of airII.1.2.10ConclusionCharacterization of selected systemsII.1.3Characterization of selected systemsMartin SchmidtInstitut f¨u r Physik der Ernst-Moritz-Arndt-Universit¨a t Greifswald,Felix-Hausdorff-Str.6,D-17489Greifswald,Ger-manyThis book is aiming at an introduction into plasma chemistry.Therefore,only a subset of the complete plasma chemistry can be covered.New applications of e.g.thinfilm deposition techniques,surface treatment procedures,and substance transformation processes in the volume controlled by plasma chemical reactions were developed the last years.Process improvement in terms of products determined by specific elementary processes is ongoing intensive development and research as can be seen from literature.Due to this dynamic development in thisfield a data base for plasma chemistry will be outdated rather soon. Therefore,a study of reference journals and data bases like NIST,permanently reflecting improved understanding in thisfield,is necessary for a discussion of new experimental results or the development of adequate models.In the following some selected topics of special interest demonstrating the broad spectrum of applications.II.1.3.1Hydrocarbon plasma chemistryThe plasma chemistry of hydrocarbons is characterized that the important reaction channels are initiated by electron impact.It offers a broad spectrum of processes and even applications beyond standard organic chemistry.The spectrum ranges from complicated processes of the formation of bioorganic compounds in the early earth atmosphere,natural gas reformation, polymeric depositions and creation of higher hydrocarbons to deposition of diamond-like thinfilms and creation of pure carbon as soot or even diamond.One essential starting substance is the methane molecule.The plasma chemistry of methane is often initiated by electron impact dissociation leading to CH3radicals and H ato+ms[1]CH4+e−CH3+H+e−.(II.1)Figure II.1:Reaction scheme of the transformation of C1H x and C2H yspecies in diamond plasma CVD according to[2].M indi-cates the action of the wall.Another pathway is the reaction of this molecule with hydrogen atoms(also generated by electron impact processes)[3]CH4+H CH3+H2.(II.2)The abstraction of further H atoms leading to CH2,CH,and C is possible by H atoms but also by electron collisions,especially in pure methane plasmas.The reverse reaction, the addition of H atom to CH3to form CH4occurs at low temperature[4].H atoms may be generated by dissociative electron collisions of H2molecules,at higher gas temperatures thermal dissociation of hydrogen molecules becomes dominant as studied in thermal plasma chemistry.Here,some processes may be more effective,but the specific production sensitivity of non-thermal plasma chemistry is lost due to generations of new compounds in a cold gaseous environment.A reaction scheme is presented in Fig.II.1for the formation of CH x and C2H y compounds controlled by collisions of hydrocarbon molecules with H atoms[2].Concerning the variety of the processes in a H2-CH4plasma,including the electron impact induced reactions,see also[5].II.1.3.1.1Origin of life on earthOne exciting and still not completely resolved topic is the origin and the development of live on the earth.Thefirst step is the formation of organic molecules,e.g.amino ler [6]observed in a plasma chemical experiment in spark discharges for a mixture of methane, ammonia,hydrogen,water vapour and liquid water under the action of UV radiation the formation of various organic compounds as HCN,amines,aldehydes,acrylonitrile.In the solution,amino acids were formed.The products in the gas phase were generated by the action of free radicals and ions of the gas discharge.The state of the early earth atmosphere is discussed by Abelson[7].An N2–CO–H2atmo-sphere is supposed and HCN and H2O were the principal products of a gas discharge,beside small amounts of CO2and CH4.HCN in aqueous solution can lead to other interesting compounds.Also the plasma chemistry in CH2–H2S[8]and CH4–PH3[9]atmospheres is studied to detect pre-biochemical compounds.Sulphur containing reaction products are CS2and thiols as CH3SH and C2H5SH.The main organo-phosphorus product is CH3PH2.A discussion of the reaction pathways leads to the proposalCH3+PH2+M CH3PH2+M.(II.3) The radicals CH3and PH2are generated by reaction of hydrogen atoms with the CH4and PH3molecules.These experiments show the formation of organic compounds in plasma chemical experi-ments,but a detailed understanding of the processes is still lacking.II.1.3.1.2Methane conversionA very important topic is the methane conversion.Methane is a dominant part of natural gas.Other sources are petroleum processing off-gas and biogas.It is an important energy carrier and initial compound of chemical industry but also a dangerous greenhouse gas.Besides classical chemical procedures plasma chemical methods are investigated for methane transformation into higher hydrocarbons.The principle process scheme(Fig.II.1)shows the formation of ethane,ethylene and acetylene.An investigation of methane conversion in a pulsed microwave discharge(p=30mbar)yields a selectivity of acetylene generation near70percent with an energy input of10eV/molecule.Here the methane dissociation is initiated by electron impact.The generated H atoms provide the source for H abstraction of the methane molecule[10].The conversion of a CH4/CO2mixture into higher hydrocarbons or synthesis gas(CO/H2) in a hybrid catalytic plasma reactor is reviewed by[11].The chemical reactions are initiated by electron impact dissociation of CO2and CH4generating CO and O as well as CH3and H,respectively.An important research topic is the direct conversion of methane and carbon dioxide to methanol[12,13].The investigation of the reaction products of a methane-CO2 mixture in an atmospheric pressure dielectric barrier discharge shows a small concentration of methanol,but a lot of other pure and oxygenated hydrocarbons.A carbon chain growth is supposed to occur mainly by the reactionC n H2n+2+CH4C n+1H2n+4+H2.(II.4) According to the practical application an essential problem is the bad selectivity of the plasma processes,as it is shown in the diagram in Fig.II.2[13]and pointed out by[14]. Products of the methane conversion include syngas(H2+CO),gaseous products as ethylene, acetylene,and propylene,liquid hydrocarbons,plasma polymers and oxygenates.II.1.3.1.3Plasma polymerizationPlasma polymerization is a process of thinfilm deposition on electrodes,walls,or on a substrate under the action of plasmas.The plasma contains small or higher concentrations of organic molecules.The term polymerization is misleading because this material is not a polymer consisting of equal components,but it is a highly cross linked,brittle material with good dielectric properties,pinhole free,low solubility,chemical inertness and good adhesion to the surface.A broad spectrum of organic compounds was applied for plasma polymerization.In contrary to chemical polymerization these starting compounds in the feed gas can be free of double or multiple bonds or cyclic structures.In classical chemistry these substances cannot be used as monomers for polymerization.A reaction scheme of plasma polymerization can be given as follows Fig.II.3[15,16].The starting gas is activated in the plasma by electron collisions or by collisions with other energetic plasma components as H atoms.Ionic or neutral radicals are created.The target surface is activated e.g.by ion bombardment.The radicals diffuse(neutral)orflow(ionic) to the surface where they are bonded to the surface.The starting material can also move directly to the surface where a plasma induced polymerization is possible.The generationFigure II.2:Dominant chemical processes in atmospheric pressure DBDin a(CH4/CO2mixture).DME dimethyl ether CH3-O-CH3,MF methyl formate CH3-O-CH=O,ETO ethylene oxide H2C O CH2,PO propylene oxide H2CO CH CH3,Ac acetone CH3-C O-CH3[13].of non-polymer forming gas as H2may be initiated in the interaction of the plasma with the starting gas,during thefilm formation process or by the plasma interaction with the plasma polymer.An interesting feed gas for plasma polymerization is the vapor of the silicon organic com-pound hexamethyldisiloxane(CH3)3SiOSi(CH3)3).This compound is important because it can change the properties of the resulting polymers starting with nearly organic,silicone-like properties[17]using the pure compound under mild plasma conditions up to nearly nonorganic properties under the action of higher O2admixtures for SiO2-like[18]thinfilm.Figure II.3:Reaction scheme of plasma polymerization[15,16].The activation of the HMDSO molecule by electron impact ionization results in the scission of the Si-C and Si-O bond generating(CH3)3SiOSi(CH3)+2ions and CH3radicals or Si(CH3)+3 ions and OSi(CH3)3radicals,respectively[19].These products are observed also in ion molecule reactions of HMDSO molecules with Ar+ions[20].The gas phase ion chemistry is studied by mass spectrometric methods[21–23].The formation of oligomeric species with masses221,309,295,369up to383amu by reactions of fragment ions with neutral HMDSO molecules is reported.It is supposed,that the thinfilm deposition is essentially determined by the ions arriving to the surface[21,22,24].II.1.3.1.4Thinfilm deposition of metal compoundsA method of thinfilm deposition of simple metal compounds is the plasma enhanced chemical vapor deposition with metal organic starting gases.The advantage of this method is e.g. the low substrate temperature und is therefore useful for temperature sensitive materials [25].A study of deposition of TiN using Tetrakis(diethylamine)titanium(TDEAT)shows the importance of H-radicals in the H2plasma for the stripping of TDEAT.The formation of TiN requires N2addition to the process[26].The deposition of thinfilms of pure metals or simple metal compounds is possible by sput-tering in inert gas low pressure discharges and by reactive sputter deposition.An example is the deposition of TiNfilms.The nitride formation is a surface process of the fresh deposited Ti with the plasma activated nitrogen.II.1.3.1.5Diamond depositionPlasma assisted chemical vapour deposition enables the formation of diamond at moderate temperature and low pressure with hydrocarbons as starting compounds on non-diamond substrates.This allows the extended industrial use of the outstanding properties of the diamond,as the extreme hardness,high thermal conductivity,broad optical transparency (deep UV to far IR),wide band gap(5.4eV).In gas phase chemistry of a CH4/H2plasma the CH4molecule is activated which leads to carbon deposition with sp3(diamond)or sp2(graphite)bonding.The hydrogen atoms generated in the plasma etch the deposited carbon producing volatile compounds CH n(n=1−4).Because the etch rate of graphite is approximately100times higher than for diamond[27]diamond remains on the substrate. For the diamond synthesis the principle growth species are CH3,C2and H[28].In the con-ventional H2rich plasma in H2/CH4the CH3radical is responsible for the diamond growth. In H2poor plasmas,as in Ar/H2/CH4gas mixtures C2controls the diamond deposition.A variety of reactions and transformation processes in a CH4/H2plasma is illustrated by the reaction scheme Fig.II.1.The radicals C2,CH,H,CH3are observed by tuneable infrared diode laser and emission spectroscopy,respectively[2,29].The action of the H atoms is manifold for the diamond deposition process.Besides the already mentioned etching of the graphite phase and the importance for CH3generation theH atoms essentially control the chemistry of the diamond surface during the growth phase[28].Apart from the CH4/H2gas mixture also other gases were used for diamond deposition. Admixtures like CO2,O2,CO also N2and inert gases Ar,Xe or as carbon carrier e.g. chloro-andfluoro-carbons are successfully applied in deposition experiments.Bachmann[27] investigated the diamond deposition area in the C/H/O triangle phase diagram by analysis of hundreds of diamond CVD experiments with various C/H/O containing gas mixtures. Diamond growths near the“CO-line(C/O=1).Hotfilament chemical vapour deposition process and microwave plasma CVD with low or higher energy input were the most successfully applied methods for diamond deposition [28].High substrate temperatures(typically>700C)ensure good diamond quality.For various industrially important applications as deposition on microelectronic substrates lower substrate temperatures are necessary.The decrease of the deposition rate with decreas-ing substrate temperature could be compensated using other starting gases as halogenated compounds like C2H5Cl[30]or CO[31]with H2admixtures.The low temperature diamond deposition is investigated by Tsugawa[32]by a non-thermal microwave plasma with substrate temperatures from100–500C.The plasma was sustained by surface waves excited by an array of two sets of eight coaxial linear antennas powered by 2.45GHz,at a maximum of20kW.The feed gas consists of H2,CH4,CO2(∼100:1:1). The CO2admixture enhances the etching of the non-diamond depositions,especially at lowtemperatures.The discharge operates at a pressure of100Pa.Data are reported of plasma parameter(n e=1011cm−3,T e=1.5eV)measured by Langmuir probes at a typical position of the substrate.A deposition rate of the nano-diamond coating of about50nm/h was observed.The diamond single crystal growth in a high microwave power density plasma,which will be nearly a thermal plasma,is discussed by Archard[33].For microwave power densities of about100Wcm−3gas pressures near200mbar the plasma has the role to heat the gas.For gas temperatures of the gas of1000-2000C and of the substrate near1000C,H2is thermally dissociated and CH3is generated by CH4+H CH3+H2.A growth rate is observed e.g. increasing from2μm/h up to16μm/h for CH4admixtures in H2of2–8%at a power density of100W/cm3.A more detailed discussion of the plasma assisted diamond deposition is given in chapter xx.The deposition of well-ordered nanostructures as nanotips and nanotubes, nanowalls,ultrananocristalline diamond is also observed under plasma conditions using as source material mixtures of carbon-carrier gases as hydrocarbon,fluorcarbons etc.[34–39], see also[40].Fullerenes are generated successfully in thermal plasmas[34].II.1.3.2Deposition of silicon solar cellsThe development of alternative energy sources to fossil fuels is an important task for science and technology in the21st century.Photovoltaic is a promising candidate in future renewable energy technology.Thin Si-films are expected to be successful material for effective solar cells[41,42].Beside other methods plasma enhanced chemical vapor deposition is widely used for generation of amorphous silicon(a-Si:H)and microcrystalline(c-Si:H)films.Feed gas for plasma assisted silicon deposition are mainly monosilane SiH4or SiH4/H2mixtures. Inside the plasma silane is dissociated by electron impact into SiH3,SiH2,SiH,Si,H2and H,and H2in H atoms.Also SiH+x,SiH−x and H+x ions are generated.Secondary ion molecule reactions and reactions between neutral species have to be taken into account,too.Data on silane plasma chemistry are reviewed in[43].SiH3reaching the surface reacts to SiH4with bonded hydrogen atoms and generates dangling bonds or recombines with another SiH3to Si2H6.SiH4and Si2H6are desorbed from the surface.An on the surface diffusing SiH3radical reacts of with the site of dangling bond by formation of a Si-Si bond,the Sifilm is growing[41].The formation ofμc-Si:H is enhanced by high hydrogen dilution and low RF power conditions.The high optical absorption coefficient for sunlight of a-Si:H allows the application offilms with a thickness lower1μm for solar cells.The low temperature plasma enhanced deposition process(150–300C)enables the deposition on temperature sensitive substrates as polymer foils.The fabrication of homogenous large-area a-Si:Hfilms with high deposition rate is impor-tant for applications from an economical viewpoint.Parallel plate rf-reactors operating at 13.56MHz are usually used.Deposition rates of0.2-0.3nm/s are observed.Rates of2nm/s were achieved by increased operating frequency(70MHz).Table II.1:Etching gases for various materials[45–48].Material Etching gasesSilicon CF4/O2,CF2/Cl2,CF3/Cl,SF6/O2/Cl2,Cl2/H2/C2F2/CCl4,C2ClF5/O2,SiF4/O2,NF3,CCl4,C2ClF5/SF6,C2F6/CF3Cl,Br2,CF3Cl/Br2,HBrSiO2CF4/H2,C2F6,C3F8,C4F8,C4F6,C5F8,CHF3/O2Si3N4CF4/O2/H2,C2F6,C3F8,CHF3,NF3,CHF3/O2,CH3F,SF6Organics,Polymers O2,CF4/O2,SF6/O2Silicides CF4/O2,NF3,SF6/Cl2,CF4/Cl2Al BCl3,BCl3/Cl2,CCl4Cl2/BCl3,SiCl4/Cl2Cr Cl2,CCl4Cl2Cu Cl2/ArMo,Nb,Ta,Ti,W CF4/O2,SF6/O2,NF3/H2Au C2Cl2F4,Cl2,CClF3GaAs BCl3/Ar,Cl2/O2/H2,CCl2/F2/O2/Ar/He,CCl4,PCl3,HCl,Br2,COCl2,SiCl4InP CH4/H2,C2H6/H2,Cl2/Ar,Cl2/O2,HBr,CF3Br,Br2,IBr,HI,CH3I,I2,IClNiFeCo Ar/Cl2,N2/Cl2,H2/Cl2The deposition rate ofμc-Si:H could be increased by application of a narrow gap discharge at higher pressures[44].II.1.3.3Plasma etchingPlasma etching is a fundamental technology for patterning in chip production microelectronic industry.For this process a non-reactive gas is fed into the plasma where it is activated. The interaction of this activated gas with a solid substrate generates in a chemical reaction a volatile compound which contains atoms of the substrate.Gases for etching of various ma-terials are presented in Tab.II.1.An example is the silicon etching by afluorine compound as CF4.The plasma activation leads to generation offluorine atoms by electron impact dissociation of the CF4molecule.CF4+e−CF3+F+e−.(II.5) Thefluorine atom reacts with silicon and produces volatile SiF4Si+4F→SiF4.(II.6) This is only the gross reaction.A detailed model of the silicon etching by a CF4plasma is given by Standaert[50],see also[49]and Fig.II.4.Fluorine atoms F as are adsorbed onto bare silicon sites and the silicon is passivated by chemisorption(=Si-F).Activation energyFigure II.4:Reaction scheme of etching of Si by in a CF4plasma througha polymerfilm[49].for desorption of the etch product SiF n is transferred from the plasma to the surface by ion bombardment(I+).Because of the existence offluorocarbon radicals(CF n)a polymerfilm is deposited on the silicon surface.Now thefluorine atoms are adsorbed of the polymer surface (F s).They diffuse through the polymerfilm and are adsorbed by the silicon sites.Ions provide the desorption energy for the etch products,which diffuse through the polymer into the gas phase.Thefluorine atoms generated inside the plasma can also etch the polymerfilm. This model illustrates the diversity of the etch process.Only a complex treatment of the various volume and surface reactions leads to an understanding of this process.The sidewall protection by the thin polymericfilm is important for the anisotropy of trench etching. Fundamental starting processes of activating the etching gases are the electron-molecule collisions.A critical review of data for a lot offluorine and chlorine containing gases is given by Christophorou and Olthoff[51].II.1.3.4Air,nitrogen,and oxygen plasma chemistryChemical reactions in a non-thermal oxygen,nitrogen or air plasma are initiated by electron impact.The main processes are dissociation of molecules with the generation of the reactive atoms(O,N)[52,53],the formation of excited atoms and molecules as well as ions.The formation of negative ions is important mainly for the electronegative gas oxygen.The dissociative attachment of electrons generates negative atomic ions and oxygen atoms also. This process is important in the plasma because its threshold is essential lower,especially for excited molecules[54],than electron impact dissociation and dissociative ionization of O2.The excited states may be short lived or electronically excited metastable states.The rate coefficients for heavy particle reactions of ground state or electronically excited14CHAPTER II.FUNDAMENTALS,SOURCES AND DIAGNOSTICS species can differ by orders of magnitudeN+O2→NO+O(II.7) with k=7.7·10−17cm3mol−1s−1[55]andN(2D)+O2→NO+O(II.8) with k=5·10−12cm3mol−1s−1[56].The rate coefficient of the second reaction is much larger because the activation energy of this reaction is lowered by the potential energy of the excited reaction partner[57].Figure II.5:Diagram of primary chemical reactions in an air plasmainduced by electron impact[58].The air plasma chemistry is of interest because it is responsible for the producing of N x O y compounds,which have a key role in global environmental problems like acid rain.A scheme Fig.II.5of the plasma chemical reactions in dry air demonstrates the complexity of the processes[58].The plasma chemistry in air and in pure oxygen has following the important applications.II.1.SPECIFICS OF NON-THERMAL PLASMA CHEMISTRY15 II.1.3.4.1Ozone generationOzone a result of the three body collision processO+O2+M→O3+M→O3+M,(II.9) where M is a third collision partner as O2,O,also O3or N2.Oxygen atoms are generated by dissociative electron impact.The Ozone formation is reduced by competitive reactions like recombination of two O atoms to O2or reactions of O atoms with ozone molecules O+ O3+M→2O2+M[59].In chapter xxx!!!!!!!!!!!!!!!!the ozone synthesis is discussed in detail.II.1.3.4.2Plasma ashingThe interaction of an oxygen plasma with hydrocarbon compounds leads to CO2and H2O.In microelectronic industry the photoresist mask is removed(stripped)by an oxygen plasma. Damage of the semiconductor material by high energy ions must be avoided by low ion energies and highfluxes of neutral radicals i.e.oxygen atoms to the resist surface.The plasma ashing procedure is used also for quantitative analysis of lignite for separation of organic and non-organic components[60].This method is successfully applied for the preparation of samples for electron microscopic investigations[61].The advantage of plasma ashing is the low temperature of the process,because the active particles are the oxygen atoms.The reaction temperature is low as40C,molecular oxygen need reaction temperatures higher than600C[62].The formation of the high reactive ozone must be taken into account in atmospheric pressure discharges.Oxygen plasma procedures are also used for ashing of organicfilters in asbestos analytic.Such plasmas are applicable to cleaning of metallic surfaces of organic substances as grease or oil[63].Hazardous gaseous organic moleculesmay be destroyed by reactive species like N∗2,(A3S+u),N∗2(B3P g),O∗2(a1D g),O(1D),O(3P),H.OH,and N best into CO2or H2O[64].II.1.3.5ConclusionsSelected examples of the various possibilities of plasma chemical processes were presented. Most applications concern surface processes,e.g.thinfilm deposition,etching and cleaning, and to a lower extent volume processes,like voc‘s destruction.Only one volume process for the generation of larger amounts of material has reached technical maturity,namely the ozone synthesis.Some processes and procedures are specific for plasma processing.Examples are the micro patterning in microelectronics,or the deposition of plasma polymers on various substrats.The aim of future technical developments must be to enhance the selectivity and energy efficiency of plasma chemical processes,research may lead to new materials with exciting properties.。