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1、第五章材料的制备1・提拉法中,控制晶体品质的因素主要有哪些?Inthepreparationofcrystalwithpullingmethod,whatfactorscaninfluencethequalityofcrystal?答:提拉法中,控制晶体品质的主耍因素有固液界面的温度梯度、生长速率、转晶速率以及熔体的流体效应等。Answer:Inthepreparationofcrystalwithpullingmethod,factorsinfluencethequalityofcrystalincludetemperaturegradientons
2、olid-liquidinterface,growthrate,crystalspinrate,andfluideffectofmelt・2.单晶硅棒和厚度约lpm的薄膜分别可用什么方法制备?HowtoprepareSiliconrodsandthickfilmabout1pm?答:1)单晶硅棒可以用品体生长技术中的提拉法来制备,即将硅原料熔体盛放在圮圳中,籽晶杆带着籽晶由上而下插入熔体,由于固液界面附近的熔体维持一定的过冷度,熔体沿籽晶结晶,以一定速度提拉并且逆时针旋转籽晶杆,随着籽晶的逐渐上升,生长成单晶硅棒。2)厚度约1um的单晶硅薄膜可用阴极溅
3、射法制备,即利用高能粒子轰击固体靶材表面(Si),使得靶材表面的原子或原子团获得能量并逸出表面,然后在基片的表面沉积形成单晶硅薄膜。Answer:1)SiliconrodscanbepreparedbyCzochralskicrystalgrowthtechnology,thatistosay,putthesiliconrawmaterialmeltinthecrucibleandinserttheseedrodwithaseedcrystalintothemeltfromtoptobottom.Meltnearthesolid-liquidinter
4、facemaintainsacertaindegreeofsupercooling,thenthemeltcrystallizealongtheseed・Pulltheseedrodatacertainspeedandrotateitcounterclockwise,withthegradualincreaseoftheseed,growintosiliconrods.2)Monocrystallincsiliconthinfilmofl
5、imthickcanbepreparedbycathodesputtering.Usingenergeticpar
6、ticlebombardthesurfaceofthesolidtarget(Si),andthetargetsurfaceatomsorgroupsofatomsgainenergyandescapefromthesurface,andthendepositonthesurfaceofthesubstratetoformamonocrystallincsiliconthinfilm.3.液相外延法和气相沉积法都可制备薄膜,如果要制备纳米厚度的薄膜,应采用哪种方法?Bothliquidphaseepitaxymethodandvapordepositi
7、oncanbeusedtoprepairfilm,ifyouwanttoobtainfilmofnmthickness^whichmethodshouldbeselected?答:液相外延法具有设备简单、纯度高的特点,但是由于晶体成核和生长的速率较快,得到的膜较厚,很难得到纳米厚度的薄膜。物理气相沉积可通过调控蒸镀源与靶Z间的距离来调控膜沉积的速率,化学气相沉积对通过体系的温度、压力等因素來调控膜沉积的速率。因此,如果要制备纳米厚度的薄膜,应采用气相沉积法比较好。Answer:Liquidphaseepitaxymethodissimple,andth
8、epurityoffilmishigh,however,becausetherateofnucleateformationandcrystalgrowthisfast,itisdifficulttogetthemembraneofnmthickness.ForPhysicalvapordeposition,wecancontroltherateoffilmdepositionthroughregulatingthedistancebetweenthesourceandtarget.Forchemicalvapordeposition,wecancont
9、rolthefilmdepositionratebycontrollingtemperatur