Deposition (PVD and CVD)

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Plan of presentation

• Deposition methods

CVD( Chemical Vapor Deposition) PVD ( Physical Vapor Deposition )

• Principles, processes on the surface

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Deposition methods classification

2 Deposition methods PVD ( Physical Vapour Deposition Füüsikaline aurufaasist sadestamine) CVD ( Chemical Vapour Deposition – Keemikaline aurufaasist sadestamine ) 3

PVD and CVD methods

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Metalorganic CVD 8

Plasma Enhanced CVD (PECVD)

PECVD – plasma-enhanced CVD: – glow-discharge plasmas (usually RF field: 100 kHz – 40 MHz), or MW – 2.54 GHz plazma at reduced gas pressure between 50 mtorr and 5 torr) are sustained within chambers where simultaneous vapor-phase chemical reactions and film depositions occur – plasma activation of reactions (average electron energies range from 1 to 10 eV) ! chemical reactions occur at much lower temperatures than in thermal CVD Main applications of PECVD: - microelectronics (DRAM cells) - plasma modification of metal surfaces (nitriding, carburizing): the atoms of nitrogen and carbon that deposit on metal surfaces modify them by diffusing into the underlying matrix - diamond films

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Plasma Enhanced CVD (PECVD) 10

PECVD (MW) Plasma Enhanced CVD Microwave plasma chemical vapor deposition system for high quality poly-, mono- and nanocrystalline diamond films. MW frequency – 2.54 GHz.

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Diamond films Polycrystalline diamond films Nanocrystalline diamond films 12

Application of diamond films - Semiconductor Devices, RF MEMS, - Creation of novel surface materials, i.e. super ‐ hydrophobic surfaces , super ‐ hydrophilic surfaces (biocompatible surfaces) - Fabrication of 3 ‐ D diamond probes and structures for field emission - High selectivity and high voltage range electrochemical sensors and electrodes - Defects in diamond (famous NV centers) for single photon sources, quantum computers (qubit ), quantum cryptography,… - Sensors (quantum sensing in biology and medicine) - Tribology

Current research projects in our Department include:

-Growth of the diamond tips for Atomic Force Microscopy -Investigation of the diamond films growth (fractal approach) - Investigation of tribological properties of the diamond films (nanowaves on the wear scars) …………………….

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Announce

Diamond films prepared by Chemical Vapor Deposition

Dr. V. Ralchenko , Natural Sciences Center of Prokhorov General Physics Insitute RAS, Diamond Materials Laboratory, Moscow, Russia

• • • • • Lecture agenda: 1. Chemical Vapor Deposition (CVD) of diamond films: Principles and methods 2. Growth processes for nano/micro/mono-crystalline films in microwave plasma 3. The properties of diamond films 4. Diamond films processing 5. Applications of diamond films Lecture venue - Tallinn University of Technology, Department of Materials Engineering Lecture will be held on 20 November 2013. 14

Atomic Layer deposition (CVD like) Atomic scale deposition. ALD is similar in chemistry to CVD, except that the ALD reaction breaks the CVD reaction into two half- reactions, keeping the precursor materials separate during the reaction.

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PVD – Physical Vapor Deposition Evaporation Evaporation: controllably transfer atoms from a heated source to a substrate located a distance away, where film formation and growth proceed atomistically.

Thermal energy is imparted to atoms in a liquid or solid source such that their temperature is raised to the point where they either efficiently evaporate or sublime.

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Electrically heated evaporation sources (Thermal evaporation)

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Pulsed laser deposition

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Electron-beam evaporation

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Molecular beam epitaxy

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Ion beam assisted evaporation

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Discharge based deposition methods (sputtering, arc evaporation )

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Thermal evaporation (PVD)

Termilise aurustuse põhimõtteline skeem

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Molecular beam epitaxy

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Discharge based deposition methods

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1. SPUTTERING

(katood-ioonpommitus)

Magnetron Sputtering DC RF

2. Cathode ARC ion Plating (kaarleek sadestamist)

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Voltage-current characteristics

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Sputtering (DC and RF)

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Katood-ioonpommitussadestus

Magnetron sputtering 24

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Platit π70 and π -80 28

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Coating structure

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What you need to remember

1. Difference between PVD and CVD. - PVD – evaporation or collision impact of the solid target - CVD – chemical processes in gaseous phase and the surface 2. The versatility of deposition methods is due to particular purposes including quality of the films (coating), size of sample, deposition price, …… 3. The quality of the film is a leading factor in the development of new deposition methods. Nowadays, those are: a. Layer by layer deposition :examples – MBE (PVD), ALD (CVD) b. PECVD 32

Vaba energia F = U-TS U-sisseenergia T-temperatuur S-entroopia

Mechanism of Growth

10 γΔσ = ΔF Island growth Volmer Weber Layer-by-layer Frank-van der Merwe Layer-by layer+island Stranski Krastanov 33

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