功能材料4：半导体制造技术2013概要.ppt

第三章：晶体材料与半导体加工技术Crystal Materials and Semiconductor Processing Technology 3. 1 单晶材料的基本物性 3. 2 晶体缺陷 3. 3 半导体晶体制备 3. 4 半导体芯片加工技术 3.1.2 晶体物理性质与微观对称性的关系 Relationship between the physic properties and micro-symmetry of crystals 晶体压电性：不具有中心对称的点群（20个） 晶体热释电：有唯一极轴、存在自发极化，受热后正负离子相对移动 晶体铁电性：在外电场作用下，可以自发极化 【微观缺陷】 【线缺陷】line dislocations 螺旋位错 screw dislocation 单晶硅中观察到的螺旋位错缺陷 【宏观缺陷】Macrocopic defects: §3.3 半导体晶体及晶片制备技术 Processing Technology of SemiconductorCrystal its Wafer 3.3.1 概述 Introduction The outer crust of this planet consists of all kinds of silicates (Si + O + something else). Si, in fact, accounts for about 26 % of the crust, while O about 49 %. Liquid Si indeed does react with all substances known to man - it is an universal solvent. This makes crystal growth from liquid Si somewhat tricky, because how do you contain your liquid Si? Fortunately, some materials - especially SiO2 - dissolve only very slowly. But(!!!) there will always be some dissolved SiO2 and therefore oxygen in your liquid Si, and that makes it hard to produce Si crystals with very low oxygen concentrations. 3.3.2 硅原料处理和提纯  Producing Raw Silicon and its purifying SiO2? + ?2C = Si + 2CO 【硅提纯】Purifying of si CVD Schematic diagram More information The chemistry is extremely dangerous: AsH3 and PH3 are among the most poisonous substances known to mankind; PH3 was actually used as a toxic gas in world war II with disastrous effects. H2 and SiHCl3 are easily combustible if not outright explosive, and HCl (in gaseous form) is even more dangerous than the liquid acid and extremely corrosive. Handling these chemicals, including the safe and environmentally sound disposal, is neither easy nor cheap. ·Still, it works and abut 10.000 tons of poly-Si are produced at present (2000) with this technology, which was pioneered by Siemens AG in the sixties. It is not cheap, however, and has no potential too become very cheap either. The link provides today