《薄膜物理与技术》化学气相沉积.pptx

CVD;要点：

化学气相淀积的基本原理

CVD特点

CVD装置

低压CVD

等离子体化学气相淀积PECVD

金属有机物化学气相沉淀（MOCVD）;1.Introduction;化学气相淀积，简称CVD(ChemicalVaporDeposition)是把含有构成薄膜元素的一种或者几种化合物或单质气体供给基片，借助气相作用或在基片上的化学反应生成所需薄膜。;1)gasdecomposition

(1)thermaldeposition

(2)plasmadeposition

(3)photon(laser,UV)deposition

2)Kinds－accordingtotemp.,pressure,…

CVDchemicalvapordeposition

APCVDatmosphericpressure...

LPCVDlow-pressure...

VLPCVDverylowpressure…

PECVDplasma-enhanced...

LECVDlaser-enhanced...

MOCVDmetal-organic...

ECRCVDelectron-cyclotronresonance...

VPEvapor-phaseepitaxy

;3)advantages

lowcostdielectric(poly-silicon,Si3N4,SiO2)andmetalthinfilm

highdepositionrate

highorlowpressure

controlthickness,defectandresistivity

highfilmquality

LTCVDforsemiconductors,ex.,Si3N4,SiO2andepilayer

lowradioactivedamage

Buthighdepositiontempoerature;4)parametersforthinfilmstructure

(1)temperatureofsubstrateandchamber

(2)growthrate

(3)gaspressure

Theseparametersaffectonsurfacespeedoftheinvolvedatoms.

;APCVD;LPCVD;PECVD;Overview

notallcomponentsarefoundinallCVDsystems:

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Sourcegas

Reactsonsubstratetodepositfilm;2.TypesofCVDreactions

热分解－Pyrolysis-thermaldecomposition

AB(g)---A(s)+B(g)

ex:SidepositionfromSilaneat650oC

SiH4(g)---Si(s)+2H2(g)

usetodeposit:Al,Ti,Pb,Mo,Fe,Ni,B,Zr,C,Si,Ge,SiO2,Al2O3,MnO2,BN,Si3N4,GaN,Si1-xGex,...

;还原/置换－Reduction/Exchange

oftenusingH2(metal,substrate)

AX(g)+H2(g)===A(s)+HX(g)

oftenlowertemperaturethanpyrolysis

reversible=canuseforcleaningtoo

ex:Wdepositionat300oC

WF6(g)+3H2(g)===W(s)+6HF(g)

usetodeposit:Al,Ti,Sn,Ta,Nb,Cr,Mo,Fe,B,Si,Ge,TaB,TiB2,SiO2,BP,Nb3Ge,Si1-xGex,...

;氧化/氮化－Oxidation/Nitrition

oftenusingO2/N2

AX(g)+O2(g)---AO(s)+[O]X(g)

ex:SiO2depositionfromsilaneand