薄膜工学第一节

, , , , , ,2012-03-29,#,薄膜 工学,1,薄膜的成长是,?,单结晶薄膜成长, Epitaxt,薄膜成长,薄,膜的成长法,真空系,Gases, Plasma,薄,膜的特性评价,透過,电子显微镜,分析,(TEM),X-ray,回转器,分析,(XRD),原子,力显微镜 分析,(AFM),光学,性 特性评价,概略,2,References,1. Deposition Technologies for Films and Coatings,Bunshah, Noyes Publications, 1982,2. Physical Vapor Deposition of Thin Films,Mahan, John Wiley & Sons, Inc., 2000,3. Materials Science of Thin Films,Milton Ohring,4. Glow Discharge Processes: sputtering and plasma etching,Braian Chapman, John Wiley & Sons, 1980,3,光源,LD,收光元件,PD,P-Metal,n-Metal,p-AlGaAs : capping,p-AlGaAs : cladding,AlGaAs : active,n-AlGaAs : cladding,n-AlGaAs : Substrate,光通信 概略图,光纤传送途,coupler,coupler,4,笔记本的,TFT-LCD,截面概略图,5,Cross-sectional view of a poly-Si/Si,0.7,Ge,0.3,/Si TFT structure,SiO,2,poly-Si,poly-Si,0.7,Ge,0.3,poly-Si,metal,gate oxide,gate poly-Si,SiO,2,Y,Y,Schematic diagram,Cross-sectional TEM micrograph,6,薄膜的必要性,高密度化,高技能化,高神速化,低价格化,輕薄短小,充分满足现代产业社会需求的条件所必须具备的要求,7,为了获取一定量的电场而所需的电压,E =,V,1,d,1,E,V,1,d,1,E= 3000 kV/m,d,1,= 1 cm = 10,-2,m,V,1,= 30 kV,Bulk,的情况,E =,V,2,d,2,E,V,2,d,2,E,2,= 3000 kV/m,d,2,= 1,m,m = 10,-6,m,V,2,= 3 V,薄膜的情况,2,8,什么是制造薄膜？,玻璃板表面被水覆盖的现象,准备玻璃板,-,用喷雾器在表面进行喷雾,-,形成小的水滴,-,再用喷雾器喷雾,-,小水滴变大,-,水滴相互接触,-,水将覆盖有所得表面,9,薄膜的形成是和这个非常相似的,蒸发时所出现的原子,(,原子,分子, cluster,等,),在模板上发生冷却、附着的现象,非结晶,:,冷却的原子,random,排列,结晶质,:,冷却的原子在模板表面,surface migration,进行周期性的、,规则性的原子排列,10,制造薄膜时必须考虑薄膜的特性,材料的多样性,薄膜和模板之间的粘着力,Step coverage,不纯物的影响,11,Properties of Thin Film,High surface-to-volume ratio,Physical properties of thin films are no longer same as,those of bulk.,eg) existence of surface energy states.,different crystal structure.,different interatomic distance.,The behavior of coating/substrate combination depends on ;,1) the properties of the two components,2) the interaction between the two adhesion,12,Unique Features of Deposited Materials,Extreme versatility of range and variety of deposited materials.,Overlay coatings with properties independent of the thermodynamic compositional constraints (Mg,x,Zn,1-x,O),Generation of microstructures different from conventionally processed materials, e.g., a wide range of microstructures-ultrafine (submicron grain to nano) to single crystal films.,Ability to vary defect concentration over wide limits, thus resulting in a range of properties comparable to, or far removed from conventionally fabricated materials.,High quench rates available to deposit amorphous materials.,13,Diffusion vs. Overlay coatings,-,Diffusion coatings are produced by the complete interdiffusion of material applied to the surface into the bulk of the substrate materials,eg) Oxide formation by oxygen diffusion,Impurity doping by diffusion or ion implantation.,- Overlay coating is an add on to the substrate surface,eg) superconducting film by CVD, sputtering ,pulse laser deposition,Si epitaxial growth by CVD,14,Applications of Coatings,Electrical function ; microelectronic devices(IC,VLSI.) , electrical conductors, insulators, electrical contacts, solid state devices, solar cells, superconducting film.,Optical function ; laser optics, IR dectector, photodetector, mirrors, antireflective coatings, selective solar absorbers.,Mechanical function ; wear resistant coatings, lubrication films, hard coating for cutting tools.,Chemical function ; anti-oxidation coatings, corrosion resistant coatings, catalytic coatings.,Decorative function ; eye glass frames, costume jewelry.,15,薄,膜的结晶性以及,配向性,（,control,）,-,为了应用薄膜的特性，所以在薄膜制造的时候非常重要。,非晶质,:,short range ordering,结晶质,:,short range ordering + long range ordering,-,单结晶,:,原子或是分子进行快速规则性的排列,-,多重结晶,:,由很多微小结晶所构成,-,epitaxy:,在模板结晶上成长其他结晶的情况，这种结晶为了模,板结晶，将向特定的方向成长,薄,膜的,結晶性,16, ,Polycrystalline thin film,Epitaxial thin film,G.B. Scattering,light loss,low conductivity,Domain Boundary,17,Epitaxial BaTiO,3,thin film growth on SrTiO,3,Using Chemical Solution Deposition Method,850,o,C, 30 sec,1000,o,C, 30 sec,BaTiO,3,SrTiO,3,grains,epitaxial layer,18,High-Resolution Transmission Electron Microscopy,Direct obsevation of atomic arrangement of a material (0.2 nm),(interface, precipitates, defects analysis at an atomic level),HRTEM micrograph of (111)CdTe/(001)GaAs epitaxial structure,grown by molecular beam epitaxy. (B=110),19,薄膜,制造,技术,PVD,(Physical Vapor Deposition),Evaporation,Thermal Evaporation,Electron Beam Evaporation,Sputtering,DC/RF Sputtering,Magnetron Sputtering,Ion Beam Sputtering,Ion Plating,Ion Beam Assisted Deposition,Pulsed Laser Deposition,CVD (Chemical Vapor Deposition),Thermal CVD,Low Temp. CVD: Plasma CVD, Photon CVD,Laser Assisted CVD,MOCVD (Metal Organic Chemical Vapor Deposition),MBE (Molecular Beam Epitaxy),Thermal Spraying,Electroplating,sol-gel),薄膜工程的技术分类,20,Thin Film Coating, ,21,未完待续,22,