3. Comparison of ALD and CVD
Schematic pressure profile during the ALD and CVD process
SPePunTg-DMEoSLIeGe Net al., ChemPhysChem, 12, 791-798(2011)
3. Comparison of ALD and CVD
4.2 Coatings on nanoparticles
ALD Cycles → Bowl Thickness PPT DESIGN
PS Spheres → Bowl Size
4.3 Combination of CNT and super-black coatings
PPT DESIGN
4.3 Combination of CNT and super-black coatings
Deposition at reduced substrate temperatures Increased choice of precursors and materials Good control of stoichiometry and composition
operating pressure, power, exposure time, biasing voltage
原子层沉积法的原理和应用
Synthetic Chemistry of Materials
Aห้องสมุดไป่ตู้omic Layer Deposition (ALD)
杨 超、包 峰、方 聪、蒋博瀚、马 红石 李勇辉、王 谦、徐 晨、于 浩、 赵灿灿
—Shanghai Institute of Ceramics
PPT DESIGN
2. Classical models: ALD of Al2O3
The surface chemistry during Al2O3 ALD
(a) AlOH* + Al(CH3)3 AlOAl(CH3)2*+CH4 (b) AlCH3* + H2O AlOH*+CH4
The overall reaction for Al2O3 ALD
2Al(CH3)3+ 3H2O
PPT DESIGN
Al2O3+3CH4 ∆H=376 kcal
1. Introduction to ALD
Atomic layer deposition （ALD） — atomic level control of film deposition
1 Atomic level control
4.1 Coatings on high aspect ratio structures
1 Coating on step-like sructures
1 2
2 Coating on multi-pore structures
MP. KPnTauDt,EetSaIlG. MNicroelectron Eng, 107, 80-83 (2013)
XiPnPWTanDg,EeSt aIGl.,NACS Appl. Mater. Interfaces,3: 4180-4184 (2011)
4.4 Merits of Plasma-Assisted ALD
❖Merits
Improved material properties
film density, impurity content, electronic properties
Increased growth rate
NP. PLeTicDkE, JS. IVGaNc. Sci. Technol. A 29, 021016 (2011)
4.4 Plasma-Assisted ALD Configurations
Schematic illustration of the ALD and CVD process for the synthesis of CNT arrays
Schematic representation of Al2O3 ALD coating on monodispersed NPs.
Kai Zhou, et al., Nanoscale Res Lett, 5:1555-1560(2010)
Atomic level control
I can’t
Sequential introduction of
precursors
ALD CVD
Synchronous introduction of
precursors
Better step coverage
PPT DESIGN
Existing shadowing effects
4.2 Coatings on nanoparticles
PS spheres self assembled ALD of TiCl4 and H2O Ion milling Etching PS hemispheres Annealing
XPuPDTonDgEWSaInGgNet al., Nano letters Vol.4,No.11 (2004)
2 Self-limiting
Characters
3 Conformal deposition 4 Pinhole-free films
PPT DESIGN
5 High repeatability and expansibility 6 Substrate（Large and high aspect ratio）
Outline
PPT DESIGN
Outline
1.Introduction to ALD 2.Classical models: ALD of Al2O3 3.ALD and CVD 4.Applications of ALD
(1)Coatings on high aspect ratio structures (2)Coatings on Nanoparticles (3)Combination of CNT (4)Plasma ALD 5. Expectations and challenge in ALD